EXCITATION OF MAGNESIUM ATOMS IN HOLLOW CATHODE DISCHARGE

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EXCITATION OF MAGNESIUM ATOMS IN HOLLOW CATHODE DISCHARGE

F. Kidrasov

To cite this version:

F. Kidrasov. EXCITATION OF MAGNESIUM ATOMS IN HOLLOW CATHODE DISCHARGE.

Journal de Physique Colloques, 1979, 40 (C7), pp.C7-121-C7-122. �10.1051/jphyscol:1979760�. �jpa- 00219466�

JOURNAL DE PHYSIQUE CoZZoque C7, suppZ6ment au n07, Tome 40, JuiZZet 1979, page C7- 121

EXCITATION OF MAGNESIUM ATOMS IN MILLOW CATWOE DlSCHARGE

F.Kh. Kidrasov.

Bashkirian S t a t e PedagogicaZ I n s t i t u t e , Ufa, U. S . S. R.

3 3

1

In

this paper magnesium atoms triplet _1,

. ^{33p0, 3}

^pf

^{, 3}

^{p2; m}

- ³

^pl.

3 3

3

POl2 and

4

S states excitation mecha-

1 The direct electron excitation rate

nism investigation r e m l t e are presented. 00

The experiments were carried out at helium pressure of 0.65 Torr and discharge

current ranging within 20

-

50 mA. The ^Vok

,,

^{( 2 )}

discharge tube constraction, data of elec- where-

no

-

averaged along the length of so- trokinetic, spectrally-optic parameters urce ground state concentration

of Mg atoms;

of magnesium hollow cathode discharge f i l -

nej- electron concentration i n the led with argon and helium were given in point ^J along the axis;

/ lr2 ^{/ O} Qok(V)

-

the direct excitation cross-

section of the level k;

Mg atoms

3

3

Pol*

states considered as

-

the distance between two points one state were established to be populated ^A'J j along the axis in which the

second derivative curves iY(V) under our experimental conditions mainly

through direct electron excitation but do- minant mechanism of their decay nas the stepwise transitions to 3 ' ~ ; resonanoe le- vel and metastable states death on tube walls due to the diffusion.

Consequently for

3

3

Pol*

states the balance equation can be put down as

where

dok

i s direct electron excitation rate;

O(km

i s stepwise transitions rate;

of electron c u m e n t to the3probe are measured.

The

c&k

values were evaluated. by using of tight-binding approximation cross- section /

3 /.

Energy dependence of Qo,(V) to a range of greate energies was approxi- mated by one of intercombination X -4571

1 3

( 3 So

- ^{3 P1}

^{) line /4}

/.

The concentra- tion

Go

of Mg atoms in ground state ne- cessary for the calculation of

wok

is de- termined from self-reversed resonance

0 1 1

A =

²⁸⁵²

^A

⁽

³

^So

- ³

^{PI )} spectral line profile by method of /

5

/.

pk

.is the diffusion metastable atoms The stepwise transitions rat:OLkm i s escape rate.

calculated according to the simular to The sum in the equation ( 1 ) means

( 1 ) equation in which

E0

is replaced the rates one of three considered states:

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1979760

by

Gk -

concentration of Mg atoms in le- vel k, Qok(V) by Qkm(V)

-

^a stepwise exci- tation cross-section and Vok by Vkm=Vm-Vk- energy of transition. The stepwise excita- tion croso-section is obtained from Gryzin- ski's formula / 6 /. The concentrations of

3 3 3

Mg atoms in 3 Po, 3 P1 and 3 P2 states we-

ns

determined from data of 5167, 5173 and

0 0

5184 M lines reabsorption measurements.

The diffusion metastable atoms escape rate is

p

=

-

n k w

,

^{( 3 )}

where metastable states decay probability W is calculated according to the kinetic theory of gas.

The separate members of equation ( 1 ) calculation results are given in Table 1.

Table 7 The members of the balance equation ( 1 1, 10"4sm-3e-~

As it is seen from Table 1 the consi- dered processes of population and depopu- lation of Mg

3

3

POl2

states take place un- der the conditions of our experiment, how- ever one may remark the decay going mainly due to the transitions to

3

1 P1 resonance bevel.

The calculations showed that main me- chaniem of ?dg

4

3 S1 level population is also direct electron excitation but the

3 3 depopulation takes place at the

4

S1-3 POl2 spontaneous transitions, i.e, the balance equation for i =

4

3 S1 may be written as

oi

$

^{'ik * ( 4 )}

3

3 3

where k =3 Po, 3 PI,

3

P2, Nik is the 3 3

4

S1-3 POl2 spontaeous transitions rate.

Table 2 The members of the ba1anc.e equation ( 4 ),

In Table 2 one can see the results of calculations according to (

4

) with the use of our experimental electron energy distribution functions and data of cross- sections /

4 /.

The apontaneous transiti- ons rates Nik were obtained from = 5167, 5173, 5184

(43~1 -

^{33~012) spectral}

lines absolute intensities measurements.

The balance of Mg

4 ' s 1

state atoma under the investigated experimental con- ditions also holds good ( Table 2 ).

R E F E R E N C E S

' t .Kidrasov F.Kh, ,Dsvyatov A . I . ,Volkova L.M., Arkhipova L.V. XI ICPIG, Pra e, 1973,119.

TBT, 12, 688, 1974. f?

20R3lApacO~ %X.,Z~BRTOB

A.M.,

OAKOBa J r M e

3,~abriGnt 1.1. J.Phys., g7.,

91, 1974.

4 .

A n e x c a x ~ ~

g.C, s

A

Orrss~a

s

_cnelcrp.,

54. ^{I o s , 1973.}

5,Kidrasov F.Kh. VIIqat .~onf. on Spectr.

with Foregner guests Participation, Slantchev Bryag, Sept.25-29,1976,p. 56.

6.

Gryzinski M. Phys.Rev.a, 374,1959;

' J&305,322,336,1965.