1. Renner-Teller and Spin-Orbit Coupling in H 2 S + and AsH 2 G. Duxbury 1, Christian Jungen 2 and Alex Alijah 3 1 Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow, G4 0NG, UK 2 LAC, Laboratoire Aime Cotton du CNRS, Universite de Paris -Sud, 91405 Orsay France 3 UMR CNRS 6089, Universite der Reims, Champagne- Ardenne, BP. 1039, 51687 Reims Cedex 2, France 19/06/2013MOLSPECT 2013 WG08 4:02 pm

2. Outline of the presentation AsH 2 : Photographic record of the electronic spectrum of AsH 2 Comparison of term values derived from ringdown Zhao et al. and from flash photolysis, Dixon et al. H 2 S+: Comparison of PES, electron beam induced emission, and recent MATI results 19/06/2013MOLSPECT 2013 WG08 4:02 pm

3. Analysis of the 2 A 1 to 2 B 1 electronic band system of the AsH 2 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. 19/06/2013MOLSPECT 2013 WG08 4:02 pm

4. AsH 2 Absorption spectrum recorded using flash photolysis, 1966-67. The bands analysed were v 2 =1 to v 2 =3. From v 2 =3 to v 2 =6 the predissociation increases rapidly, so that above v 2 =6 no absorption spectra could be recorded. 19/06/2013MOLSPECT 2013 WG08 4:02 pm

5. AsH 2 Spectra 2000 onwards Hughes, Brown and Evenson, “Rotational spectrum of the AsH 2 radical in its ground state”. J. Mol. Spectrosc, 200, 210 (2000) He and Cloutier, “Laser spectroscopy and dynamics of the jet-cooled AsH 2 free radical”, J. Chem. Phys, 126, 154312 (2007) Grimminger and Clouthier, AsD 2 and AsHD, J. Chem. Phys, 137, 224307 (2012) Zhao, Qin, Ji, Zhang and Chen, “Absorption spectra of the AsH 2 radical in 435-510 nm by cavity ringdown spectroscopy”, J. Mol. Spectrosc. 256, 192 (2009) 19/06/2013MOLSPECT 2013 WG08 4:02 pm

6. AsH 2 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) 19/06/2013MOLSPECT 2013 WG08 4:02 pm

7. AsH 2 term values, from Dixon, Duxbury and Lamberton, Proc. Roy. Soc, A 305, 271 (1968) & from Zhao et al. J. Mol. Spectrosc. 256 192 (2009 ) 19/06/2013MOLSPECT 2013 WG08 4:02 pm

8. AsH 2 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 ), 19/06/2013MOLSPECT 2013 WG08 4:02 pm

9. Photo-electron spectrum of H 2 S P. Baltzer et. al. Chem. Phys. 195, 403 (1995) 19/06/2013MOLSPECT 2013 WG08 4:02 pm

10. Emission spectrum of H 2 S+, 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 2 B 1 and the 4 B 1. 19/06/2013MOLSPECT 2013 WG08 4:02 pm

11. 2010 Potential curves of H 2 S + New P.E curves H 2 S +, calculations based on Hochlaf et al data. J.Chem. Phys. 120, 6944 (2004) 19/06/2013MOLSPECT 2013 WG08 4:02 pm

12. 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 19/06/2013MOLSPECT 2013 WG08 4:02 pm

13. A comparison of the the analysis of the fluorescence (DJR) and MATI (HKK)spectra 19/06/2013MOLSPECT 2013 WG08 4:02 pm

14. Conclusion The main points of this presentation are: The comparison between the different experimental methods of investigating the spectrum of AsH 2 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 H 2 S + after the barrier to linearity is reached demonstrates the changeover to quasilinear behaviour for v 2 ’ =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 v 2 ’ = 7 and above. 19/06/2013MOLSPECT 2013 WG08 4:02 pm