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He[sup *](2 [sup 3]S) penning ionization of H[sub 2]S. II. Formation of the SH[sup +](A [sup 3]Π) and H[sub 2]S[sup +](Ã [sup 2]A[sub 1]) ions.

Authors :
Tokue, Ikuo
Yamasaki, Katsuyoshi
Nanbu, Shinkoh
Source :
Journal of Chemical Physics; 9/22/2003, Vol. 119 Issue 12, p5882, 7p, 1 Chart, 8 Graphs
Publication Year :
2003

Abstract

Emissions in the 200–750 nm region produced by the collision of He[sup *](2 [sup 3]S) with H[sub 2]S were studied under single-collision conditions. The hydrogen Balmer lines and the SH[sup +](A [sup 3]Π–X [sup 3]Σ[sup -]) and H[sub 2]S[sup +](à [sup 2]A[sub 1]–X [sup 2]B[sub 1]) bands were assigned. The total emission cross section (σ[sub em]) was evaluated to be (1.7±0.3)×10[sup -20] m[sup 2] at a collision energy of 150 meV. The σ[sub em]s of the SH[sup +](A–X) and H[sub 2]S[sup +](ÖX) bands decreased with increase in the collision energy in the 115–200 meV range, indicating that attractive forces are effective for the incident channels with regard to the formation of these species. The rotational distribution of SH[sup +](A [sup 3]Π,ν[sup ′]=0) is represented by a Boltzmann temperature of 870±80 K. The H[sub 2]S[sup +](à [sup 2]A[sub 1]–X [sup 2]B[sub 1]) emission, which was assigned for the first time in the Penning ionization of H[sub 2]S, primarily consists of the bending progressions. The internal populations of H[sub 2]S[sup +](Ã) were analyzed using the vibrational energies and Einstein’s A coefficients calculated in this study. The details of the calculation and derived spectroscopic constants are reported in the accompanying paper, Paper I. The populations obtained for the bending vibration (ν[sub 2][sup ′]) of H[sub 2]S[sup +](Ã) show an inverted distribution with a peak at ν[sub 2][sup ′]=3. This distribution is shifted lower compared that with a peak at ν[sub 2][sup ′]=4–5 observed by He[sup *](2 [sup 3]S) Penning ionization electron spectroscopy and that with a peak at ν[sub 2][sup ′]=6–7 predicted by the theoretical Franck–Condon factors for the H[sub 2]S(X)–H[sub 2]S[sup +](Ã) ionization. The origin of the difference is discussed concerning the formation mechanism of H[sub 2]S[sup +](à [sup 2]A[sub 1]). © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
119
Issue :
12
Database :
Complementary Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
10719072
Full Text :
https://doi.org/10.1063/1.1602064