MOLSPECT 2013 WG08 4:02 pm

Renner-Teller and Spin-Orbit Coupling in H2S+ and AsH2

G. Duxbury1, Christian Jungen2

and Alex Alijah3

1Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow, G4 0NG, UK

2LAC, Laboratoire Aime Cotton du CNRS, Universite de Paris -Sud, 91405 Orsay France

3UMR CNRS 6089, Universite der Reims, Champagne-Ardenne, BP. 1039, 51687 Reims Cedex 2, France

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Outline of the presentation• AsH2:• Photographic record of the electronic spectrum of

AsH2

• Comparison of term values derived from ringdown Zhao et al. and from flash photolysis, Dixon et al.

• H2S+: • Comparison of PES, electron beam induced

emission, and recent MATI results

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Analysis of the 2A1 to 2B1 electronic band system of the AsH2 Radicals

• The absorption spectrum of this band system was first recorded in absorption by Dixon, Duxbury and Lamberton, Proc.Roy.Soc. A305, 271 (1968).

• Apart from one limited series of measurement of its emission spectrum By T Ni and colleagues in 1986 (Chem. Phys. Lett. 126, 417-420), no detailed studies were carried out until the period from 2000.

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AsH2 Absorption spectrum recorded using flash photolysis, 1966-67.

The bands analysed were v2=1 to v2=3. From v2=3 to v2=6 the predissociation increases rapidly, so that above v2=6 no absorption spectra could be recorded.

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AsH2 Spectra 2000 onwards• Hughes, Brown and Evenson, “Rotational spectrum of the

AsH2 radical in its ground state”. J. Mol. Spectrosc, 200, 210 (2000)

• He and Cloutier, “Laser spectroscopy and dynamics of the jet-cooled AsH2 free radical”, J. Chem. Phys, 126, 154312 (2007)

• Grimminger and Clouthier, AsD2 and AsHD, J. Chem. Phys, 137, 224307 (2012)

• Zhao, Qin, Ji, Zhang and Chen, “Absorption spectra of the AsH2 radical in 435-510 nm by cavity ringdown spectroscopy”, J. Mol. Spectrosc. 256, 192 (2009)

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AsH2 term values, derived from Zhao,Qin, Ji, Zhang and and Chen, J. Mol. Spectrosc. 256 192 (2009) and from Hughes, Brown and Evenson J. Mol.

Spectrosc, 200,210 (2000)

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AsH2 term values, from Dixon, Duxbury and Lamberton , Proc. Roy. Soc, A 305, 271 (1968) &

from Zhao et al. J. Mol. Spectrosc. 256 192 (2009)

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AsH2 term values, from Dixon, Duxbury and Lamberton , Proc. Roy. Soc, A 305, 271 (1968)and from Hughes, Brown

and Evenson J. Mol. Spectrosc, 200,210 (2000),

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Photo-electron spectrum of H2SP. Baltzer et. al. Chem. Phys. 195, 403 (1995)

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Emission spectrum of H2S+,G. Duxbury, Ch. Jungen and J. Rostas 1983

Duxbury, Jungen and Rostas (1983)

1972, only half the resonances in v’ = 5 and 6 identified by Duxbury, Horani and Rostas.

D,J,R 1983 calculations allow details of resonances to be calculated.

Breaking off of emission is due to predissociation induced by interaction between the X 2B1 and the 4B1.

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2010 Potential curves of H2S+

• New P.E curves H2S+, calculations based on Hochlaf et al data.

• J.Chem. Phys. 120, 6944 (2004)

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Mati results, Han S., Kang T.Y and Kim S.K, J. Chem. Phys. 132, 124304, (2010)

• These results from Han and his colleagues may be compared with electronic emission spectra shown earlier.

• The sub- band studied is part of the 0,6,0 to 0,0,0 band system shown in the earlier slide. Their numbering has been revised to 0,6,0.

• The K=2 sub-band was not assigned in our earlier work as the emission spectrum breaks off due to predissociation

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A comparison of the the analysis of the fluorescence (DJR) and MATI (HKK)spectra

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Conclusion• The main points of this presentation are:

• The comparison between the different experimental methods of investigating the spectrum of AsH2 and of the hydrogen sulphide ion.

• Different barrier heights give rise to very different spectra

• The need to use an appropriate partitioning of the large amplitude Hamiltonian. The rapid increase of the splitting of the the K’=0 and K’=1 subbands of H2S+ after the barrier to linearity is reached demonstrates the changeover to quasilinear behaviour for v2

’=5 and above.

• The high resolution MATI spectra of Han, Kang and Kim allow higher ro-vibronic levels levels to be seen above the predissociation threshold, in particular for v2

’= 7 and above.

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