Absorption in the spectral range of the Schumann-Runge bands

(1)

1834 CANADIAN JOURNAL OF

CHEMISTRY. VOL.

47, 1969

3. R. E. HUFFMAN. Handbook of geophysics and space environments. Edited by S. Valle. McGraw- Hill Book Co., Inc., New York. 1965. DASA reaction rate handbook, DASA 1948. Defense Atomic Sup- port Agency, Washington. 1967.

4. G. L. WEISSLER. Handbuch der Physik. Vol. XXI.

Edited by S. Flugge. Springer-Verlag, Berlin. 1956.

5. J. A. R. SAMSON. Techniques of vacuum ultraviolet spectroscopy. John Wiley and Sons, Inc., New York.

1967

6. J:R.'MCNESBY and H. OKABE. Advan. Photochem.

3,147 (1964).

7. A. C. G. MITCHELL and M. W. ZEMANSKY. Reso- nance radiation and excited atoms. Cambridge Uni- versity Press, London. 1934.

8. R. M. GOODY. Atmospheric radiation. I. Theoreti- cal basis. The Clarendon Press, Oxford. 1964.

9. A. J. BLAKE, J. H. CARVER, and G. N. HADDAD. J.

Quant. Spectry. Radiative Transfer, 6,451 (1966).

10. J. A. R. S ~ ~ s o ~ a n d R. B. CAIRNS. J. Geophys. Res.

69,4583 (1964).

11. V. D. MEYER, A. SKERBELE, and E. N. LASSETTRE. J.

Chem. Phys. 43,3769 (1965).

12. J. A. R. SAMSON. Advan. At. Mol. Phys. 2, 177 (1966).

13. G. V. MARR. Photoionization processes in gases.

Academic Press, Inc., New York. 1967.

14. R. W. DITCHBURN and P. A. YOUNG. J. Atmo- spheric Terrest. Phys. 24, 127 (1962).

15. B. A. THOMPSON, P. HARTECK, and R. R. REEVES.

J. Geophys. Res. 68,6431 (1963).

16. P. H. METZGER and G. R. COOK. J. Quant. Spectry.

Radiative Transfer, 4,107 (1964).

17. R. E. HUFFMAN, Y. TANAKA, and J. C. LARRABEE.

Discussions Faraday Soc. 37,154 (1964).

18. R. GOLDSTEIN and F. N. MASTRUP. J. Opt. SOC.

Am. 56.765 (1966).

19. J. 0. SULLIVAN &d P. WARNECK. J. Chem. Phys.

46,953 (1967).

20. R. A. YOUNG and G. BLACK. J. Chem. Phys. 47, 2311 (1967).

21. J. S. EVANS and C. J. SCHEXNAMER. NASA Technical R e ~ o r t R-92 (1961).

22. R. D. HUDSON, V. L. CARTER, and J. A. STEIN. J.

Geophys. Res. 71,2295 (1966).

23. R. E. HUFFMAN, J. C. LARRABEE, and Y. TANAKA.

J. Chem. Phys. 40,356 (1964).

24. G . R. COOK and P. H. METZGER. J. Chem. Phys.

41,321 (1964).

25. F. M. MATSUNAGA and K. WATANABE. Sci. Light, Tokyo, 16,31(1967).

26. W. F. J. EVANS, D. M. HUNTEN, E. J. LLEWELLYN, and A. VALLANCE JONES. J. G e o ~ h y s .

-

- Res. 73.2885 (1968).

27. R. P. WAYNE. Quart. J. Roy. Meteorol. Soc. 93, 69 (1967).

28. R. E.' HUFFMAN, J. C. LARRABEE, and Y. TANAKA.

J. Chem. Phys. 46,2213 (1967).

J. Chem. Phvs. 47.4462 (1967).

30. F. ALBERT]; R. 'A. ASHBY,' and A. E. DOUGLAS.

Can. J. Phys. 46,337 (1968).

J. Chem. Phys. 39,910(1963).

32. K. CODLING. Astrophys. J. 143,552(1966).

33. J. P. APPLETON and M. STEINBERG. J. Chem. Phys.

46.1521 (1967).

34. G.' M. LAWRACE, D. L. MICKEY, and K. DRESSLER.

J. Chem. Phys. 48,1989 (1968).

35. M. OGAWA and R. B. CAIRNS. Planetary Space Sci.

12,656 (1964).

36. A. DALGARNO, R. J. W. HENRY, and A. L. STEWART.

Planetary Space Sci. 12, 235 (1964), and references therein. ^- ^~^~^~^-^-^-

37. R. B. CAIRNS and J. A. R. SAMSON. Phys. Rev. 139, A1403 (1965).

38. F. J. COMES, F. SPEIER, and A. ELZER. Z. Natur- forsch. 23a, 114 (1968).

39. R. J. W. HENRY. Planetarv S ~ a c e Sci. 15. 1747 40. R. E.' HUFFMAN, J. C. LARRABEE, and Y. TANAKA.

Phys. Rev. Letters, 16,1033 (1966).

41. E. C. Y. INN and Y. TANAKA. J. Opt. SOC. Am. 43, 870 (1953).

42. E. VIGROUX. Ann. Phys. 8,709 (1953).

43. P. A. LEIGHTON. Photochemistrv of air ~ollution.

Academic Press, Inc., New York. f961. p. 48.

44. E. VIGROUX. Ann. Phys. 2,209 (1967).

45. W. B. DEMORE and 0. RAPER. J. Chem. Phys. 44, 1780 (1966).

46. L. A. HALL, W. SCHWEIZER, and H. E. HINTEREGGER.

J. G e o ~ h v s . Res. 70.105 (1965).

47. J. A. R..SAMSON and R. B. 'CAIRNS. J. Opt. SOC.

Am. 55,1035 (1965).

48. R. E. HUFFMAN and J. C. LARRABEE. J. Geophys.

Res. 73,7419 (1968).

49. R. P. WAYNE. Privatecommunication.

50. J. C. LARRABEE and R. E. HUFFMAN. Un~ublished results.

Absorption in the spectral range of the Schumann-Runge bands

M. ACKERMAN, F. BIAUME,

AND

M. NICOLET

Znstitut D'Ae'ronomie Spatiale de Belgique 3, Avenue Circulaire, Bruxelles 18, Belgique Received November 21, 1968

Absorption of silicon lines by O2 in the Schumam-Runge bands has been measured. The results lead to some conclusions about the nature of the absorption and about the general behavior of the spectrum.

Canadian Journal of Chemistry, 47, 1834 (1969)

Introduction Runge bands (1750-2000 A) and in the Herzberg Early measurements, presented in Fig. 1, of the continuum ( h < 2424 A) were mainly performed absorption coefficient of oxygen in the Schumann- with light sources providing spectral emission

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14 For personal use only.

1834 CANADIAN JOURNAL OF CHEMISTRY. VOL. 47, 1969

3. R. E. HUFFMAN. Handbook of geophysics and space environments. Edited by S. Valle. McGraw- Hill Book Co., Inc., New York. 1965. DASA reaction rate handbook, DASA 1948. Defense Atomic Sup- port Agency, Washington. 1967.

4. G. L. WEISSLER. Handbuch der Physik. Vol. XXI.

Edited by S. Flugge. Springer-Verlag, Berlin. 1956.

5. J. A. R. SAMSON. Techniques of vacuum ultraviolet spectroscopy. John Wiley and Sons, Inc., New York.

1967.

6. J. R. McNESBY and H. OKABE. Advan. Photochem.

3,147 (1964).

7. A. C. G. MITCHELL and M. W. ZEMANSKY. Reso- nance radiation and excited atoms. Cambridge Uni- versity Press, London. 1934.

8. R. M. GOODY. Atmospheric radiation. I. Theoreti- cal basis. The Clarendon Press, Oxford. 1964.

9. A. J. BLAKE, J. H. CARVER, and G. N. HADDAD. J.

Quant. Spectry. Radiative Transfer, 6, 451 (1966).

10. J. A. R. SAMSON and R. B. CAIRNS. J. Geophys. Res.

69,4583 (1964).

11. V. D. MEYER, A. SKERBELE, and E. N. LASSEITRE. J.

Chern. Phys. 43, 3769 (1965).

12. J. A. R. SAMSON. Advan. At. Mol. Phys. 2, 177 (1966).

13. G. V. MARR. Photoionization processes in gases.

Academic Press, Inc., New York. 1967.

14. R. W. DITCHBURN and P. A. YOUNG. J. Atmo- spheric Terrest. Phys. 24, 127 (1962).

15. B. A. THOMPSON, P. HARTECK, and R. R. REEVES.

J. Geophys. Res. 68, 6431 (1963).

16. P. H. METZGER and G. R. COOK. J. Quant. Spectry.

Radiative Transfer, 4, 107 (1964).

Discussions Faraday Soc. 37,154 (1964).

18. R. GOLDSTEIN and F. N. MASTRUP. J. Opt. Soc.

Am. 56, 765 (1966).

19. J. O. SULLIVAN and P. WARNECK. J. Chern. Phys.

46,953 (1967).

20. R. A. YOUNG and G. BLACK. J. Chern. Phys. 47, 2311 (1967).

21. J. S. EVANS and C. J. SCHEXNAYDER. NASA Technical Report R-92 (1961).

22. R. D. HUDSON, V. L. CARTER, and J. A. STEIN. J.

Geophys. Res. 71,2295 (1966).

J. Chern. Phys. 40, 356 (1964).

24. G. R. COOK and P. H. METZGER. J. Chern. Phys.

41, 321 (1964).

25. F. M. MATSUNAGA and K. WATANABE. Sci. Light, Tokyo, 16, 31 (1967).

26. W. F. J. EVANS, D. M. HUNTEN, E. J. LLEWELLYN, and A. VALLANCE JONES. J. Geophys. Res. 73, 2885 (1968).

27. R. P. WAYNE. Quart. J. Roy. Meteorol. Soc. 93, 69 (1967).

J. Chern. Phys. 46, 2213 (1967).

J. Chern. Phys. 47, 4462 (1967).

30. F. ALBERTI, R. A. ASHBY, and A. E. DOUGLAS.

Can. J. Phys. 46, 337 (1968).

J. Chern. Phys. 39, 910(1963).

32. K. CODLING. Astrophys. J. 143, 552 (1966).

33. J. P. ApPLETON and M. STEINBERG. J. Chern. Phys.

46, 1521 (1967).

34. G. M. LAWRENCE, D. L. MICKEY, and K. DRESSLER.

J. Chern. Phys. 48,1989 (1968).

35. M. OGAWA and R. B. CAIRNS. Planetary Space Sci.

12,656 (1964).

36. A. DALGARNO, R. J. W. HENRY, and A. L. STEWART.

Planetary Space Sci. 12, 235 (1964), and references therein.

37. R. B. CAIRNS and J. A. R. SAMSON. Phys. Rev. 139, A1403 (1965).

38. F. J. COMES, F. SPEIER, and A. ELZER. Z. Natur- forsch. 23a, 114 (1968).

39. R. J. W. HENRY. Planetary Space Sci. 15, 1747 (1967).

Phys. Rev. Letters, 16, 1033 (1966).

41. E. C. Y. INN and Y. TANAKA. J. Opt. Soc. Am. 43, 870 (1953).

42. E. VIGROUX. Ann. Phys. 8, 709 (1953).

43. P. A. LEIGHTON. Photochemistry of air pollution.

Academic Press, Inc., New York. 1961. p. 48.

44. E. VIGROUX. Ann. Phys. 2, 209 (1967).

45. W. B. DEMoRE and O. RAPER. J. Chern. Phys. 44, 1780 (1966).

46. L. A. HALL, W. SCHWEIZER, and H. E. HINTEREGGER.

J. Geophys. Res. 70,105 (1965).

47. J. A. R. SAMSON and R. B. CAIRNS. J. Opt. Soc.

Am. 55, 1035 (1965).

48. R. E. HUFFMAN and J. C. LARRABEE. J. Geophys.

Res. 73,7419 (1968).

49. R. P. WAYNE. Private communication.

50. J. C. LARRABEE and R. E. HUFFMAN. Unpublished results.

Absorption in the spectral range of the Schumann-Runge bands

M. ^ACKERMAN,F. BIAUME, AND M. ^NICOLET

Institut D'Aeronomie Spatiale de Belgique 3, Avenue Circulaire, Bruxelles 18, Belgique Received November 21, 1968

Absorption of silicon lines by O2 in the Schumann-Runge bands has been measured. The results lead to some conclusions about the nature of the absorption and about the general behavior of the spectrum.

Canadian Journal of Chemistry, 47, 1834 (1969)

Introduction

Early measurements, presented in Fig. 1, of the absorption coefficient of oxygen in the Schumann-

Runge bands (1750-2000 A) and in the Herzberg

continuum (A. < 2424 A) were mainly performed

with light sources providing spectral emission

(2)

ACKERMAN ET AL.: ABSORPTION IN THE RANGE O F SCHUMANN-RUNGE BANDS

WAVELENGTH (

A

1

1800 1900 2000 ZlW 2200 2300 2400

5

M O L E C U L A R O X Y G E N

2

r6l9

O KREUSLER (1901)

5 GRANATH (1929)

A BUISSON ET COLL. (1933) X VASSY (1911

2

8 WATANABE (1953) 1eZ0

V WlLKlNSON ET MULLIKEN (1957) BETHKE ( 1 959 I

5 O DITCHBURN ET YOUNG (1962)

-

2

N

5

-21

-

¹⁰

z

0 - t s

W U1 U1 U1

:

²

0 10 -22

! FIG. 1. Absorption cross section of molecular oxygen oo between 1700 and 2430

A.

The uncertainty remaining in the Schumam-Runge bands after measurements extending20ver a period of more than 60 years appears clearly.

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14 For personal use only.

ACKERMAN ET AL.: ABSORPTION IN THE RANGE OF SCHUMANN-RUNGE BANDS

1800

1020 f-

~i

N ^~_z^E¹⁶²¹^f-

1

^C)

C)

0

...

u UJ VI VI VI 0

'"

u

1022 f-

0

1623 f-

_24

10 58 57 56 55 54 1900

111

1-.:....

I" II

\ 11\

1,\

II

\ 1

I

I, x

I· \ ••

• II

kr'

I~

.-'

^• ^•

...

^x

WAVELENGTH

(A

I

2000 2100 2200 2300

MOLECULAR OXYGEN

., KREUSlER 119011

• GRANATH (1929) II BUISSON ET Call. (1933) x ^VASSY ⁽¹⁹⁴¹¹

tI WATANABE (1953)

V WilKINSON ET MULLIKEN (1957)

t - I BETHKE (1959)

o DITCH BURN ET YOUNG (1962)

. . . .

x~ x x

I - <

0

,.,

X A

. ..

0 _III

• • •

x A

•

X x· x 0

0 ⁶

0 ^A

0

0 )( x)( x'X)(

0 ^xx Xx 0

53 52 51 50 49 48 47 46 45 44 43 WAVENUMBER l1000 cm-1 )

2400

• x

42

1835

-

D.

FIG. 1. Absorption cross section of molecular oxygen 0'0 between 1700 and 2430

A.

The uncertainty remaining in the Schumann-Runge bands after measurements extending²0ver a period of more than 60 years appears clearly.

(3)

TABLE I Data S Bethke ov0(02) 0dSi) 0dSi) Band Line vo.(cnl-') v~,(cn~-') Av(cn1-') K(crn-l) (cm) YJ (cm2) (cm2)

zo,,(OZ)

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14

For personal use only.

-

00 W 0\ TABLE I Data O"y(Si) S Bethke O"y(Si) O"YO(02) III2) Llv(em-) Llv(em-vs,(em-vo/em-I) (em2) (em) ) Band ) (emLine rJ LO"'0(02) 10.5 5-0 7P 52513.2 rO.06589 4.24x 10

0 ''} 9R 52511.9 52502.7 9.2 13.2 6.44x 10-19

t

0.07434 4.79 x 10-20 5.26x 10-22 2.99x 10-3 9P 52486.5 16.2 0.06690 4.31 x 10-20 11R 52485.5 17.2 0.06664 4.29x 10-20 6-D 19P 52823.3 52819.2 4.1 3.8 1.53x10-18 {0.01186 2.89x 1O-2o } (1. 31 x 10-21) 2.57x10-2 21R 52822.6 3.4 0.01236 1.89x 10-20 1.23xlO-21 n

>

6-0 13P 52973.4 52974.7 1.3 1.3 1.53 x 10-18 {0.05102 7.81 x 1O-2o} 0.79 x 10-20) 1.20xlO-1

z

15R 0.04198 6.42x 10-20 1.71 X 10-20

>

tl 7-D 25P 53 141.1 53 139.1 2.0 2.5 3.15x 10-18 {0.00380 1.20x 1O-2o} 8.28xlO-22 4.49 x 10-2

;;

27R 53135.6 3.5 0.00204 6.43 x 10-21 Z 53349.1 38.9

r·

^OISS6

5.94x 10

0 ''} .... 7-D 19P 0 21R 53345.4 35.2 0.01236 3.89xlO-2o

c::

53310.2 33.2 3.15x 10-18 1.50x 10-22 1.05 x 10-3 ~ 21P 53285.6 24.6 0.01180 3.72x 10-20 Z 23R 53281.4 28.8 0.00722 2.27 x 10-20

>

r< 7-D 19P 53349.1 53337.8 11. 3 9.8 3.15x 10-18 {0.01886 5.94x 1O-2o} (4.06x 10-22) 4.35xlO-3 0 21R 53345.4 7.6 0.01236 3.89x 10-20 4.28 x 10-22 "!j 7-D 17P 53406.7 19.4

r·

⁰²⁸²¹

8.89x 10

0 ''} n

:r:

19R 53403.6 16.3 0.01986 6.26x 10-20 ttl 53387.3 26.6 3.15x 10-18 3.14x 10-22 1.26xlO-3 is: 19P 53349.1 38.2 0.01886 5.94x 10-20

v.:

21R 53345.4 41.9 0.01236 3.89x 10-20 >-I ~ 8-D 13P 54000.4 18.5

r·

^05I02

3.05x 10

0 ''}

:<

15R 53995.3 53981. 9 13.4 22.5 5.98x10-18 0.04198 2.51 x 10-19 0.19 x 10-21) 1.14x 10-3 < 15P 53953.5 28.4 0.03936 2.35x 10-19 1.11 x 10-21 0 17R 53947.8 34.1 0.02987 1.79xlO-19 l' 0.40 x 10-20) .... 8-D 13R 54036.8 54034.4 2.4 2.4 5.98xlO-18 0.05494 3.29x 10-19 3.98xlO-2 ... 1.31 X 10-20 ~ 8-D 7P 54104.1 13.4 rO.06589 3.94XIO

O "}

'"

'" 9R 54101. 5 54090.7 10.8 14.4 5.98x10-18

t

0.07434 4.45 x 10-19 (2.96x 10-21) 2.07x 10-3 9P 54075.6 15.1 0.06690 4.00x 10-19 3.39 X 10-21 11R 54072.2 18.5 0.06664 3.99x 10-19 8-0 7P 54104.1 54108.2 4.1 5.5 5.98 x 10-18 {0.06589 3.94x 1O-19} (6.95 x 10-21) 9.19x 10-3 9R 54101. 5 6.7 0.07434 4.45 x 10-19 7.71xlO-21 8-0 5P 54126.7 54128.0 1.3 2.4 5.98x 10-18 {0.05637 3.37x 1O-19} (3.20 x 10-20) 4.87 x 10-2 7R 54124.7 3.3 0.07530 4.50x 10-19 3.83 x 10-20 8-0 1R 54157.3 10.6 {0.02726 1.63x 10

0 ''} 1P} 54152.7 54167.9 15.2 13.4 5.98xlO-18 0.01363 8.15x 10-20 0.71 x 10-21) 3.01 x 10-3 3R 0.05110 3.05xlO-19 1.85 x 10-21 9-D 23P 54158.0 9.9 9.49 x 10-18 0.00692 6.57x 10-20

(4)

ACKERMAN ET AL.: ABSORPTION IN THE RANGE OF SCHUMANN-RUNGE BANDS

m_I m

-

_I m_I r

-

_I m_I

^:

r_I _I _I ^P_I ^P_I _l ^P_l _I^P * ^P_I

-

^P_I ³^P_I ³^P_I ^P³_I ³^P_I ³^P_I ^-^P_I ^M^P_I

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

I I

i i

X X X X X X X X x x x x X X X X X X X X X X

CO o\

% 3 z % ? % ?

- - I - - o \ o \ o q m m

"9

z g E 2 F z z z

v, 0, m A m 3 ~ -

- -

^N' ^N ^N' ^N ^N N N N ' N ' N '

I--

-

b o o 1 ~ - O ~ m m e m N O N C O C O W r-r-

? y \ q q m oq m - m w w e N o - w c\com m w e 8 - w \ o r - * 8 w w o \ m, o \ y y o \ m m

. . .

w w n m .

r- N corn-

-

^\d ^&\d

^Ad:

^&d p i \ d & 0 0 & o ; d & & o d & & o N ' & - m - C O W m m v , m v , o o

v, v, - v , m m m o w v , m \ o - m r - t- - 0 co w w r - W~COWWI--I--I--CO

-

^{- - N} ^{m m m}^{m v ,}^{0 0}

- -

^{N - N}

^a ^, ^, ^, ^, ^--,, ^, ^, ^, ^, ^, ^,

b b e b b b b e b w w w I--r-

g g g g g

^{e b b e}^v,^v,mv,v,^v,^{m v ,}^v,^{w w w}W W W W W W W W ~ W W W W W W W v,v, v , ( A v, v , m v , v , v, m v , v, v,v,v, m v , v , m v , m v , v , ' n v, m m v , m v , v , v,v, m v ,

-

wQ

f 6 9

-

^,,2 2 2 2""

^*

2: ^{+ y i 7}2 " m " " " " " " " " " " " ^6+7--" " 0

" " " " "

m m

2 x 2 x x 2 2 _I _I _I _I _I _I _I

x

_I ^{" 0} _I ₁ ₁ ₁ ₁ ₁ _I _I _l _l _I-4_I-_I-_I-_I*_I3_I*_I3_I

-

_I ³_I ^-_l^-_l _I³^-_l ^-_l _{I 1 1}^{* * * -}₁

2 2 2 2 2 2 2 44 44 2 2 2 2 2 2 44 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

X X X X X X X x X X x x X X X X X X x x X X X X x x X X X X X X X X X X X X X X X X X X m m m w r - N N N m m m o w w r-v, w e e v,v,v,ebeooo b b b b m v , C O ~

W - O m m -

. . .

.

. . -

^m

.

r - m m a N m b W m r- - 0 .

---

m m m - - - m m m N . . . . . N N m m a d

. . --

^v,N

- m m w w -

- - ^A, ^{+ m} ^v;

v ; m m N ' &

A : -

k t ; & \ d \ d \ d r ; r - r ; m m m w w w w w w w w w m v ;

.- 0 ^A ^? ^- ^N ^O N m - m m - m m ,.,,- ~ m

- - m m m -

a a a a a a 2

^{a a}^{m m m n}âe!â^mâe!ce!^,ma- â^{m - m}â&^{r - a}â~e!e!e!gaagde!$p:d g g ~ d g d g ~ ~ c i g

N N N N - N - - - - - N - - -

- ^- ^-

-z -

5

- 9

s

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14 For personal use only.

TABLE I (Concluded) SBethke crv/02) crvCSi) crvCSi) Band Line vo 2(em-

l )

vSl(em-

l )

Av(em-I) Av(em-I) (em) rj (em2) (em2) Lcrvo(02) 8-D 1R 54157.3 28.0

r

²⁷² ' 163x IO-"} 1P} 54152.7 32.6 5.98xlO-18 0.01363 8.15x 10-20 3R 54185.3 33.2 0.05110 3.05 x 10-19 (5.50x 10-22) 6.43 x 10-4 9-0 23R 54218.6 33.3 0.00722 6.86x 10-20 5.12x 10-22 23P 54158.0 27.3 9.49x 10-18 0.00692 6.57x 10-20 > 21P 54231. 8 46.5 0.01180 1.12xlO-19 (2.06x 10-21)

(") ~ 9-0 21P 54231.8 54236.7 4.9 4.9 9.49 x 10-18 0.01180 1.12x 10-19 2.11 x 10-21 1.88xlO-2 tTl ~ (6.57 x 10-21) a:: 10-0 29P 54306.3 54305.1 1.2 1.2 1.38x10-17 0.00096 1.32x 10-20 5.71xlO-1 > 7.54xlO-21 Z tTl 9-D 19P 54298.1 15.7 9.49x 10-18 0.01886 1.79X10-19} (2.95 x 10-22) >-j 1O-D 29P 54306.3 54313.8 7.5 15.2 1.38x 10-17 0.00096 1. 32 x 10-20 2.87x 10-22 1.49 x 10-3 > t"' 9-D 13P 54462.6 54451.1 11.5 7.9 9.49x10-18 {0.05102 4.85XlO-19} (5.27x 10-21) 4.80x 10-3 15R 54454.6 3.5 0.04198 3.99xlO-19 4.24x 10-21 > 0; 10-{) 3P 55037.4 55038.0 0.6 0.6 1.38x10-17 0.03883 5.29xlO-19 1.60x 10-19 3.02 X 10-1 en 0 ll-D 17P 55160.2 35.8

r·

⁰²⁸²¹

5.39x IO-"} ~ '"C 19R 55 142.0 55 124.4 17.6 32.8 1.91xlO-17 0.01986 3.79xlO-19 (1.51 x 10-21) 1.25 x 10-3 ::l 19P 55096.1 28.3 0.01886 3.60x 10-19 1.90 x 10-21 0 Z 21R 55073.6 50.8 0.01236 2.36x 10-19

Z

ll-D 13P 55270.9 55276.0 5.1 5.1 1.91 x 10-17 0.05102 9. 74x 10-19 1.15xlO-2O 1.18 X 10-2 >-j 11-0 lIP 55314.8 55309.4 5.4 6.2 1.91xlO-17 {0.06109 1.17XlO-18} 1.21xlO-2O 5.45 x 10-3

:r

l3R 55302.3 7.1 0.05494 1.05 x 10-18 tTl ~ 14-0 7P2.3 55280.37 56280.19 0.18 0.18 2.87x 10-17 0.04392 1.26x 10-18 1.58 x 10-18 1.25 >

z

15-0 9R1 56465.75 2.01 {0.02478 7.14x 1O-19 } Cl R2 56469.41 56467.75 1.66 1.97 2.89 x 10-17 0.02478 7.14xlO-19 4.24x 10-20 1. 98 X 10-2 tTl R3 56470.00 2.25 0.02478 7.14x 10-19 0 'l1 15-D 7P1 56485.54 8.45

rm:

6.35 x

10-"1

en P2 56488.60 11.51 6.35xl0-19 (")

:r

P3 56488.60 11 .51 2.89x 10-17 0.02196 6.35 x 10-19 c::: 9R1 56465.75 11.34 0.02478 7.14xl0-19 a:: > R2 56469.41 56477 .09 7.68 8.29 0.02478 7.14xlO-"

r

1.23 x 10-20 2.35x10-3 Z R3 56470.00 7.09 0.02478 7.14x 10-19

z

16-D 15R1 56472.60 4.49 0.01399 3.90x 10-19

10

R2 56479.69 2.60 2.80x 10-17 0.01399 3.90x 10-19 c::: Z R3 56481.92 4.83 0.01399 3.90x 10-19

J

Cl 16-D 9P1 56613.38 56613.79 0.41 0.41 2.80x 10-17 0.02230 6.24x 10-19 3.46 X 10-19 5.54x 10-1 tTl 0; 16-D 9P2 56617.93 5.20

r

0 .02230 6.24x 10-19 } >

z

P3 56618.84 56623.13 4.29 4.69 2.80x 10-17

L

0.02230 6.24x 10-19 2.65x10-2O 1.36x 10-2 t::I Rl 56627.72 4.59 0.02480 6.94x 10-19 en 16-0 9Rz 56633.90 3.38 2.80x 10-17 {0.02478 6.94x 10-19~ R3 56633.32 56637.28 3.96 3.19 0.02478 6.94x 10-19 1.42 x 10-19 7.76 X 10-z 17-D 13P1 56635.58 !.70 2.60x 10-17 0.01701 4.42x 10-19

J

16-D 7P2 56655.68 56656.27 0.59 0.59 2.80x 10-17 {0.02196 6.15X10-19} 1.00x 10-18 8.13xl0-1 P3 56655.68 0.02196 6.15 x 10-19 ... 16-0 3P1 56700 37 2.80x 10-17 0.01278 3.58x 10-19} 00 56700.25 0.12 0.12 9.25 x 10-19 1.04 W 17-0 11P2 56700.37 2.60x 10-17 0.02036 5.29x10-19 -..J Norc Values oblained with the 2.17 m length cell are shown in parentheses; others were obtained with the 4.01 m length cell.

(5)

1838 CANADIAN JOURNAL OF ( ZHEMISTRY.

VOL.

^{47, 1969}

lines ( 1 4 ) . Differences between measured values

were not clearly understood before analysis of the rotational structure by Curry and Herzberg (5), Knauss and Ballard (6), and Brix and Herzberg (7), all of whom used continuous light sources and high resolution spectrographs.

Absorption measurements by Watanabe, Inn, and Zelikoff (8) using a hydrogen light source showed an apparent pressure effect due to in- sufficient resolution. They lead to an order of magnitude of absorption intensity useful for semiquantitative applications. Using a slightly higher resolution and assuming the spectral line width, Ditchburn and Heddle (9) have deduced values of the oscillator strengths of the bands.

Such results do not agree with those of Bethke (lo), deduced from integrated absorption co- efficients measured at high pressure, or with those of Hudson (ll), obtained recently at different temperatures. This discrepancy has lead to the conclusion that the line half-widths assumed by Ditchburn and Heddle were too small.

The present article reports measurements of the absorption coefficients of 0, on more than 30 lines of atomic silicon excited in a microwave discharge tube. Such a light source, already described (12), presents various advantages; the spectral lines are narrow and their wavelengths are known with a high accuracy, the uncertainty being less than 0.0015 A. In addition, such a source produces practically no continuous radi- ation.

Experimental

The spectral lines have been isolated in our experiments using a 50 cm focal length vacuum monochromator before entering the absorption cell which was a Pyrex tube closed at each end with a quartz lens. Two cell lengths have been used, 217 and 401 cm. The light intensity was monitored by an E.M.I. 6255 Cd photomultiplier. The output was recorded for various 0, pressures measured by using mercury manometers and MacLeod gauges.

For the data obtained in the region between the 5-0 and the 17-0 band, Beer's law is obeyed and the values range from 1.5 x to 1.6 x 10-l8 cmZ and are presented in Table I. In a few cases where the wavenumber of an 0, rotational line differs only by a fraction of a cm-' from the wavenumber of a silicon line at which the measurement takes place, the absorption cross- section has a negative pressure coefficient. In such cases an inferior limit for the absorption cross-section was obtained by extrapolating to zero pressure. For lower v' values a positive pressure coefficient appears which has already been reported by others (13, 14). We shall not deal here with this part of our data.

Interpretation

The absorption at 56 700.25 cm-' of one of the Si lines corresponds to the maximum of the 3P1 line of the 16.0 band and the 1 1P2 line of the 17.0 band of 0, which are blended at 6 700.37 cm-'. We infer, from the integrated absorption coefficients given by Bethke and from the relative rotational population, that these lines have an equivalent rectangular width of 1 cm-'.

This value is not in disagreement with those given by Wilkinson and Mulliken (15), Heddle (16), and Hudson (1 I). Assuming that this value is valid for the bands that we consider here, we have calculated the maxima of absorption cross- section at the center of the lines which are close to the silicon lines. We have then plotted the ratios of the measured values o to the sum of the maximum values oi versus the distance Av in cm-', weighted according to the relation

The graph of Fig. 2 shows the absorption de- pendence of the distance from the line even at 30 cm-' from the line center. The error bars indicate only the uncertainty on the measured cross-sections. The scattering of the points can be attributed to the uncertainty of the wave- numbers for the bands having

v'

values lower than 12, to the assumption of a constant half- width and to the overlapping of the bands which affects Bethke's values.

The solid line represents Rice's formula (17) for the shape of a line broadened by predissoci- ation. To obtain the best fit of this curve with our data the half-width has to be fixed at 1.4 cm-l.

Conclusion

A line half-width of 1.4 cm-', which must be chosen to obtain the best fit to the data mainly at large values.of Av where it has the largest influence on the ratio o/oi, indicates that the band oscillator strengths given by Bethke may be too low by as much as a factor of two or three at least for the v' values smaller than 12.

No continuous absorption underlying the bands on which we report in this article can be deduced from our measurements. The data re- ported here enforce the old idea of Flory (18)

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14 For personal use only.

lines (1-4). Differences between measured values were not clearly understood before analysis of the rotational structure by Curry and Herzberg

(5),

Knauss and Ballard

(6),

and Brix and Herzberg

(7),

all of whom used continuous light sources and high resolution spectrographs.

Absorption measurements by Watanabe, Inn, and Zelikoff (8) using a hydrogen light source showed an apparent pressure effect due to in- sufficient resolution. They lead to an order of magnitude of absorption intensity useful for semiquantitative applications. Using a slightly higher resolution and assuming the spectral line width, Ditchburn and Heddle

(9)

have deduced values of the oscillator strengths of the bands.

Such results do not agree with those of Bethke

(10),

deduced from integrated absorption co- efficients measured at high pressure, or with those of Hudson

(11),

obtained recently at different temperatures. This discrepancy has lead to the conclusion that the line half-widths assumed by Ditchburn and Heddle were too small.

The present article reports measurements of the absorption coefficients of O

₂

on more than 30 lines of atomic silicon excited in a microwave discharge tube. Such a light source, already described (12), presents various advantages; the spectral lines are narrow and their wavelengths are known with a high accuracy, the uncertainty being less than 0.0015 A.

In addition, such a

source produces practically no continuous radi- ation.

Experimental

The spectral lines have been isolated in our experiments using a 50 cm focal length vacuum monochromator before entering the absorption cell which was a Pyrex tube closed at each end with a quartz lens. Two cell lengths have been used, 217 and 401 cm. The light intensity was monitored by an E.M.I. 6255 Cd photomultiplier. The output was recorded for various O2 pressures measured by using mercury manometers and MacLeod gauges.

For the data obtained in the region between the 5-0 and the 17-0 band, Beer's law is obeyed and the values range from 1.5 x 10-²²to 1.6 X 10-¹⁸cm² and are presented in Table I. In a few cases where the wavenumber of an O2 rotational line differs only by a fraction of a cm -1 from the wavenumber of a silicon line at which the measurement takes place, the absorption cross- section has a negative pressure coefficient. In such cases an inferior limit for the absorption cross-section was obtained by extrapolating to zero pressure. For lower v' values a positive pressure coefficient appears which has already been reported by others (13, 14). We shall not deal here with this part of our data.

Interpretation

The absorption at 56 700.25 cm

^-1

of one of the Si lines corresponds to the maximum of the 3P

1

line of the 16.0 band and the 11 P

2

line of the 17.0 band of O

₂

which are blended at 56700.37 cm

-1.

We infer, from the integrated absorption coefficients given by Bethke and from the relative rotational popUlation, that these lines have an equivalent rectangular width of

1

cm

-1.

This value is not in disagreement with those given by Wilkinson and Mulliken (15), Heddle (16), and Hudson (11). Assuming that this value is valid for the bands that we consider here, we have calculated the maxima of absorption cross- section at the center of the lines which are close to the silicon lines. We have then plotted the ratios of the measured values a to the sum of the maximum values a

_i

versus the distance

/).v

in cm-I, weighted according to the relation

( -1) L/).viai

/).v

cm = - - - La

i

The graph of Fig. 2 shows the absorption de- pendence of the distance from the line even at 30 cm -

1

from the line center. The error bars indicate only the uncertainty on the measured cross-sections. The scattering of the points can be attributed to the uncertainty of the wave- numbers for the bands having

Vi

values lower than 12 to the assumption of a constant half- width a~d to the overlapping of the bands which affects Bethke's values.

The solid line represents Rice's formula (17) for the shape of a line broadened by predissoci- ation. To obtain the best fit of this curve with our data the half-width has to be fixed at 1.4 cm

-1 .

Conclusion

A line half-width of 1.4 cm

-1,

which must be chosen to obtain the best fit to the data mainly at large values. of /).v where it has the largest influence on the ratio a/ai' indicates that the band oscillator strengths given by Bethke may be too low by as much as a factor of two or three at least for the

Vi

values smaller than 12.

No

continuo~s

absorption underlying the

bands on which we report in this article can be

deduced from our measurements. The data re-

ported here enforce the old idea of Flory (18)

(6)

ACKERMAN ET

AL.:

ABSORPTION I N THE RANGE OF SCHUMANN-RUNGE BANDS 1839

I I I I I I I

-

S C H U M A N N

-

R U N G E

ROTATIONAL L I N E

-

- -

-

- -

I- 0

W

-

m m a 0

0

-

- -

I I I I I I I

5 10 15 20 25 30 35 40

A v (cm-1)

FIG. 2. Ratios o/ol of the measured cross section o and calculated cross section at the line center o; vs. the distance Av from the line center.

relating to the predissociation of the oxygen molecule in the Schumann-Runge bands.

A synthetic absorption spectrum can be com- puted using a line half-width of 1.4 cm-I and Bethke's values for the band oscillator strengths.

It exhibits minima and maxima of absorption cross-section which lead to unit optical depth in the atmosphere between altitudes at 25 and 120 km. The deduction of precise values will only become possible when the position of the

lines and the strength of the bands has been accurately determined.

1. H. KREUSLER. Ann. Phys. 6,412 (1901).

2. L. P. GRANATH. Phys. Rev. 34,1045 (1929).

3. H. burs so^, C. JAUSSERAN, and P. ROUARD. Rev.

Optique, 12,70 (1933).

4. A. VASSY. Ann. Phys. Paris, 16, 145 (1941).

5. J. CURRY and G. HERZBERG. Ann. Pliysik, 5 Folge, 19,800 (1934).

6. H. P. KNAUSS and S. S. BALLARD. Phys. Rev. 48, 796 (1935).

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14 For personal use only.

ACKERMAN ET AL.: ABSORPTION IN THE RANGE OF SCHUMANN-RUNGE BANDS 1839

~ b

~ c ~

a:

z ^10-2

~

~ U 1&1 I/)

I/) I/)

a: 0 u

10-3

~ ⁰

!"-O

~9-0 '6_0~

t,,-

§.-o

~ ^Hi-O,16.0 RICE'S FORMULA

flv.: 1.4 em-'

SCHUMANN - RUNGE ROTATIONAL LINE

10-4L-______ ~ ________ ~ ________ ^{_ L}_ _ _ _ _ _ _ _ _ L _ _ _ _ _ _ _ _ _ L _ _ _ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ L _ _ _ _ _ _ _ _ _ J

10 15 20

flv (em-I)

25 30 35 40

FIG. 2. Ratios cr/cr, of the measured cross section cr and calculated cross section at the line center crt vs. the distance !l.v from the line center.

relating to the predissociation of the oxygen molecule in the Schumann-Runge bands.

A synthetic absorption spectrum can be com- puted using a line half-width of 1 A cm

-1

and Bethke's values for the band oscillator strengths.

It exhibits minima and maxima of absorption

cross-section which lead to unit optical depth in the atmosphere between altitudes at 25 and 120 km. The deduction of precise values will only become possible when the position of the

lines and the strength of the bands has been accurately determined.

1. H. KREUSLER. Ann. Phys. 6, 412 (1901).

2. L. P. GRANATH. Phys. Rev. 34,1045 (1929).

3. H. BUISSON, C. JAUSSERAN, and P. ROUARD. Rev.

Optique, 12, 70 (1933).

4. A. VASSY. Ann. Phys. Paris, 16,145 (1941).

5. J. CURRY and G. HERZBERG. Ann. Physik, 5 Folge, 19,800 (1934).

6. H. P. KNAUSS and S. S. BALLARD. Phys. Rev_ 48, 796 (1935).

(7)

1840 CANADIAN JOURNAL O F

CHEMISTRY. VOL.

47, 1969

P. BRIX and G. HERZBERG. Can. J. Phys. 32, 110 (1954).

K. W ~ T A N A B E , E. C. Y. INN, and M. ZELIKOFF. J.

Chem. Phys. 21,1026 (1953).

R. W. DITCHBURN and D. W. 0. HEDDLE. Proc.

Roy. Soc. London, Ser. A, 226,509 (1954).

G. W. BETHKE. J. Chem. Phys. 31,669 (1959).

R. D. HUDSON and V. L. CARTER. Private communication.

V. KAUFMAN, L. J. RADZIEMSKI, and K. L. ANDREW.

J. Opt. Soc. Am. 56,911 (1966).

W. HEILPERN. Helv. Phys. Acta, 14,329 (1941).

R. W. DITCHBURN and P. A. YOUNG. J. Atmo- s ~ h e r i c Terrest. Phys. 24. 127 (1962).

P. G. WILKINSON and S. M U L L ~ K E N . Astrophys.

J. 125.594 (1 957).

D-W:O.

HEDDLE.

J. Chem. Phys. 32,1889 (1960).

0. K. RICE. Phys. Rev.35,1551(1930).

P. J. FLORY. J. Chem. Phys.4,23 (1936).

Predissociation in N, and OZ1

ROBERT D. HUDSON'

AND

VIRGINIA L. CARTER

Space Physics Laboratory, Aerospace Corporation, El Segnndo, California Received November 21, 1968

An outline discussion is given of some of the complications in the measurement of absorption cross sections which arise from finite instrumental bandwidths. Application is made to data on 0' and N, from the literature.

Introduction range from 1878 to 1894 A. All three absorption In a recent paper (1) we have shown that

published absorption cross sections obtained at maxima or minima could be in error by as much as a factor of two, and that published line and band profiles are probably erroneous because of a failure to take into account the effects of finite instrumental bandwidths. In this paper we should like to present some measurements that we have performed on N,

(?),

and 0, (3) at high reso- lution, and to show that another consequence of poor resolution is a loss of information regarding the physical processes that accompany the absorption.

Results Molecular Oxygen

We would like to discuss the molecular oxygen results first. Our initial aim was to study the effect of temperature on the absorption of oxygen in the Schumann-Runge system, at an instrumental bandwidth of 0.075 A. The results of our study of the dependence of the continuum on temperature were published some time ago (4). The depen- dence of the band structure is more complicated as is indicated in Fig. 1, which covers the spectral

'This work was supported by the United States Air Force under contract number F04695-67-C-0158.

'Present address: The Joint Institute for Laboratory Astrophysics, The University of Colorado, Boulder, Colorado 80302.

traces were obtained with the same concentration of oxygen in the absorption cell, thus the effects that one sees are due entirely to the redistribution in the ground vibrational and rotational levels.

The curve at 600 OK is of special interest as the fraction of molecules in the v"

=

1 state at that temperature is 0.0234, and yet the 9-1 band obviously gives rise to more absorption than the 6-0 band. This fact reflects the large increase in Franck-Condon factors from the v"

=

0 to the v"

⁼

1 levels due in part to the relatively large (0.4A) difference between the internuclear separations of the ground x3C,- and the excited B3C,- electronic states. One of the most important findings of the analysis was that all of the upper vibrational levels from v'

=

3 to 17 were subject to predissociation, the individual rotational lines having half-widths varying from 0.5 t o 2.3 cm-l. Predissociation in these bands explains the failure, thus far, to observe fluores- cence in the Schumann-Runge bands in the upper atmosphere, and provides an additional source of atomic oxygen between 65 and 95 km, both atoms of which will be left in the 3P state with kinetic energies of up to 1 eV. We have recently measured this photodissociation rate in the laboratory, as a function of column height, at both 200 and 300" K and the resulting atomic oxygen production rate for the CIRA 1965 standard atmosphere (12) is shown in Fig. 2. The curve shown with the Schu-

Can. J. Chem. Downloaded from www.nrcresearchpress.com by UOV on 11/13/14 For personal use only.

7. P. BRIX and G. HERZBERG. Can. J. Phys. 32, 110 (1954).

8. K. WATANABE, E. C. Y. INN, and M. ZELIKOFF. J.

Chern. Phys. 21,1026 (1953).

9. R. W. DITCHBURN and D. W. O. HEDDLE. Proc.

Roy. Soc. London, Ser. A, 226, 509 (1954).

10. G. W. BETHKE. J. Chern. Phys. 31,669 (1959).

11. R. D. HUDSON and V. L. CARTER. Private communication.

12. V. KAUFMAN, L. J. RADZIEMSKI, and K. L. ANDREW.

J. Opt. Soc. Am. 56, 911 (1966).

13. W. HEILPERN. Helv. Phys. Acta, 14, 329 (1941).

14. R. W. DITCH BURN and P. A. YOUNG. J. Atmo- spheric Terrest. Phys. 24,127 (1962).

15. P. G. WILKINSON and R. S. MULLIKEN. Astrophys.

J. 125, 594 (1957).

16. D. W.

o.

HEDDLE. J. Chern. Phys. 32,1889 (1960).

17. O. K. RICE. Phys. Rev. 35,1551 (1930).

18. P. J. FLORY. J. Chern. Phys. 4,23 (1936).

Predissociation in N2 and 0/

ROBERT

D.

^HUDSON²AND VIRGINIA

L.

CARTER Space Physics Laboratory, Aerospace Corporation, El Segundo, California

Received November 21, 1968

An outline discussion is given of some of the complications in the measurement of absorption cross sections which arise from finite instrumental bandwidths. Application is made to data on Oz and N z from the literature.

Introduction

In a recent paper (I) we have shown that published absorption cross sections obtained at maxima or minima could be in error by as much as a factor of two, and that published line and band profiles are probably erroneous because of a failure to take into account the effects of finite instrumental bandwidths. In this paper we should like to present some measurements that we have performed on

N2

(2), and O

₂

(3) at high reso- lution, and to show that another consequence of poor resolution is a loss of information regarding the physical processes that accompany the absorption.

Results

Molecular Oxygen

We would like to discuss the molecular oxygen results first. Our initial aim was to study the effect of temperature on the absorption of oxygen in the Schumann-Runge system, at an instrumental bandwidth of 0.075 A. The results of our study of the dependence of the continuum on temperature were published some time ago (4). The depen- dence of the band structure is more complicated as is indicated in Fig. 1, which covers the spectral

'This work was supported by the United States Air Force under contract number F04695-67-C-0158.

zPresent address: The Joint Institute for Laboratory Astrophysics, The University of Colorado, Boulder, Colorado 80302.

range from 1878 to 1894 A. All three absorption traces were obtained with the same concentration of oxygen in the absorption cell, thus the effects that one sees are due entirely to the redistribution in the ground vibrational and rotational levels.