Study of the ν1-ν3 infrared hot band of CH3Cl35

HAL Id: jpa-00209002

https://hal.archives-ouvertes.fr/jpa-00209002

Submitted on 1 Jan 1981

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Study of the ν 1-ν 3 infrared hot band of CH3Cl35

N. Bensari-Zizi, C. Alamichel

To cite this version:

N. Bensari-Zizi, C. Alamichel. Study of the ν1-ν3 infrared hot band of CH3Cl35. Journal de Physique,

1981, 42 (2), pp.209-213. �10.1051/jphys:01981004202020900�. �jpa-00209002�

Study ^{of the} 03BD1-03BD3 infrared hot band of CH3Cl35

N. Bensari-Zizi (*) and C. Alamichel

Laboratoire de Photophysique Moléculaire du C.N.R.S. (**),

Bâtiment 213, Université de Paris-Sud, ⁹¹⁴⁰⁵ Orsay Cedex, ^France

(Reçu ^{le 10} septembre 1980, accepté ^{le 8 octobre} 1980)

Résumé.

L’étude de la bande chaude 03BD1-03BD3 ^a été effectuée en très haute résolution; ^le paramètre 03B1A3 ^{et les cons-}

tantes de distorsion centrifuge de l’état v3

1 ont été mesurés, ^{et les} valeurs, déjà ^{connues, de} 03B1B3 ^{et de} 03BD03 ^{ont été}

confirmées.

Abstract.

The study ^{of the} 03BD1-03BD3 hot band has been performed ^with very high resolution; ^the parameter 03B1A3

and the centrifugal distortion constants of the state v3

1 have been measured, ^{and the} values, already known,

of 03B1B3 ^and 03BD03 ^{have been confirmed.}

Classification

Physics ^Abstracts

33.20E

1. Introduction.

The parallel band v3 of CH3Cl

has already been studied in infrared by Holladay

and Nielsen [ 1], ^then by ^Jones, Popplewell ^and Thomp-

son [2] : they have measured the value of the centre of band v’ and obtained for oc’ ^{values in} good agree- ment with the measurements performed ^{in micro-}

wave [3, 4]. But, ^because their resolution was not good enough, they ^{were not able to show the K structure,}

so that the parameter a3 ^remained unknown,; ⁱⁿ practice ^{it was assumed} equal ^to ce[ [5].

We have studied the _vl-v3 band with _very high

resolution (0.005 cm-1) ^{and we have} obtained, ^with good accuracy, the molecular parameters ^{of the} V3

band, using the results obtained in high ^resolution (0.030 cm-1) by ^Morillon Chapey and Graner [6]

about the _{v 1} band.

2. Expérimental conditions and assignment ^{of the}

band.

We had two spectra, ^obtained by ^{G. Gue-}

lachvili on his Fourier transform interferometer

[7, 8, 9] ^{with an} optical path ^{of 80 m ;} the pressures of methyl ^{chloride are} respectively 0.35 and 2.5 torr.

These two. spectra, already described in a former paper [10] ^about the V2 ⁺ V3 band in Coriolis reso- nance with _V3 + vs, ^{were not} recorded in order to

study ^the vl-v3 band; this fact explains ^{that the}

pressure used is ^too low (even ^{at 2.5} torr), ^{and that}

we only ^{had to} study ^the isotopic species CH3Cl35.

As a matter of fact we found the _vl-v3 band by

(*) Détachée de l’Université Mohammed V, Faculté des Sciences, Charii Ibn Batouta, B.P. 1014, ^Rabat (Agdal), ^Maroc.

(**) Laboratoire associé à l’Université Paris-Sud.

chance as we were looking again ^{for the} V3 + vs band (’). ^The vl-v3 band has the classical appearance of a parallel ^band (Figs. ^la, 1 b, ^and 1 c) ; ^{we have} assigned all the sub-bands from K ⁼ 0 _up to K

6,

with values of J often reaching 30. All these assign-

ments have been confirmed by ^the combination rela-

tionships, using ^{of course the} parameters B, D J ^and D JK of the lower level with their values in the _V3 = 1

vibrational state.

’

3. Results.

3. 1 SET OF VALUES FOR B, Du J AND

D JK IN THE VIBRATIONAL STATE v 3

1.

When all the assignments ^{of lines} wère achieved, ^{we tried to} improve ^our knowledge ^{of the} parameters (2) ^B, Dj

and DJK ^involved in the combination relationships (Fig. 2). ^{For that} purpose ^we performed ^{a least} square calculation over 111 differences like :

So we found, ^{with a} standard deviation of 0.001 6 cm-1, ^the following ^{results :}

(1) ^{We did not see} any sign ^{of the} v3 + vs band except ^its crossing with v2 + V3.

(2) ^{We call them} B3, D3j ^and D3JK in the vibrational state V3

1, Bi, Du ^and D1JK in the vibrational _{state vi}

1, ^and Bo, Doj

and DOIK ⁱⁿ the fundamental state.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:01981004202020900

210

Figs. 1 a,1 1 b, c. - Parts o f the spectrum.

Fig. 2. - Scheme of the levels connected by ^the combination relationships.

As for the fundamental level Bo ^{= 0.443} 402, ^{we can} deduce oc’

^{0.003 843, value in} good agreement with the previous measurements.

3.2 DETERMINATION OF THE PARAMETERS OF THE vl-v3 BAND. - 3.2.1 First method.

Holding B3, J ^and D3 JK ^{fixe at the valùes} just found, ^and assuming that the band is not perturbed by ^{a reso-}

nance,_we then processed ^{277 lines of} Vl-V3 in a least squares calculation. The standard deviation obtained is 0.002 8 cm-1; the observed wavenumbers and ^the differences (observed-calculated wavenumbers) ^are given ^{in tables I, II, III, IV} and V. The best fitting ^is

obtained with the following values of the parameters :

In these five tables the observed wavenumbers are

given ^{in cm-1 and the} (observed-calculated) ^dite-

rences are given ^{in 10-4 cm-1.}

Table I. - QPK ^lines (K

0, 1, 2).

Table III.

QQK ^lines (K ⁼ 3, 6).

Table II.

QPK ^lines (K ⁼ 3, 4, 6).

According ^to Morillon-Chapey and Graner [6] ^the

molecular parameters ^{of the} vibrational state vi = 1

are :

We can see that their values for OCB , 1 D 1 J ^and D 1 JK ^are

very similar to ours. Now, using their values for v°

and cx1-, ^{we can deduce :}

3.2.2 Second method.

In the preceding ^calcu-

lation we have assumed that the level _v,

1 is not

perturbed, although ^{a Fermi resonance} quite likely

exists between this level and the level _{v5 = 2°.}

To get ^{rid of} any perturbation of the level _v,

1,

we have determined 131 wavenumbers QQK( J ) (Fig. 3)

by subtracting systematically ^{our observed wave-}

212

Table IV. - QRK ^lines (K

0, 1, 2).

numbers QRK(J) ^{of the} Vl-V3 band to the corres-

ponding wavenumbers QRK( J ) ^{of the} vi band, ^taken

at the reference [6]. ^{We have then} processed ^these

131 wavenumbers of the V3 ^{band in a} classical least squares calculation, holding fixed the parameters

Bo, Doj, DojK ^and DoK, as the lower level was then the fundamental ^one. It has been necessary ^to fix

Table V.

QRK ^lines (K ⁼ 3, 4, 6).

D3x

Dox ^because only three values of K (2, ^{3 and} 6)

are present among these 131 wavenumbers. We have obtained the following results with a standard deviation of 0.008 cm-1 :

4. Conclusion.

The good agreement ^obtained between both our last methods does not mean neces-

sarily ^{that the} vi

1 level is not perturbed : ^since

it is possible ^to explain ^the v 1 band with classical formulae without explicit ^resonance (but probably

with effective values of parameters v°, ai ^and oet) ^it

is quite normal that both our methods give ^similar

results. Anyway, although the V3 ^{band itself has not}

been recorded at high resolution, ^{we can consider}

that the parameters of this band are now well known.

Acknowledgments.

We thank Dr. Guelachvili

for the spectra ^we used in this study.

References [1] HOLLADAY, ^{T. M. and} NIELSEN, ^A. H., ^{J. Mol.} Spectrosc. ¹⁴

(1964) 371.

HOLLADAY, T. M., Ph. D. Thesis University of Tennessee

(August 1962).

[2] JONES, ^E. W., POPPLEWELL, ^{R. J. L. and} THOMPSON, ^H. W., Spectrochim. ^{Acta 22} (1966) ^669.

[3] ^{DE JONGH,} J. P. and DIJKERMAN, ^H. A., ^{J. Mol.} Spectrosc. ²⁵ (1968) 129.

[4] KRAITCHMAN, ^{J. and} DAILEY, ^E. F., ^{J. Chem.} Phys. ²² (1954)

1477.

[5] DUNCAN, ^J. L., J. Mol. Structure 6 (1970) ^447.

[6] MORILLON-CHAPEY, ^{M. and} GRANER, G., ^{J. Mol.} Spectrosc.

31 (1969) 155.

[7] CONNES, J., ^DELOUIS H., CONNES, P., GUELACHVILI, G., ^MAIL-

LARD, J. P. and MICHEL, G., ^Nouv. Rev. Opt. Appl. 1 (1970) ^3.

[8] GUELACHVILI, G., ^{Nouv. Rev.} Opt. Appl. ³ (1972) ^317.

[9] AMIOT, ^{C. and} GUELACHVILI, G., J. Mol. Spectrosc. ⁵⁹ (1976)

171.

[10] BENSARI-ZIZI, N., GUELACHVILI, ^{G. and} ALAMICHEL, C., ^Mol.

Phys. ³⁴ (1977) ^1131.