A comparative study of the spectroscopic features of the low-lying electronic states of H2F+ and H2Cl+ ions

作者：Chattopadhyay Anjan^*

来源：Journal of Chemical Sciences, 2010, 122(2): 259-269.

DOI：10.1007/s12039-010-0030-y

• Configuration interaction
• electronic states
• transition moment

Configuration interaction studies of H2F+ and H2Cl+ ions, using 6-311G (3d, 3p) basis sets, have revealed several, interesting differences in their spectral behaviour. Both of them are having bent ground state ((1)A(1)) equilibrium geometries, but there is a huge difference (similar to 1.93 eV) between their energy barrier to linearity. Their first two excited states are found to be linear (3)Pi(u) and (1)Pi(u) states, correlating to B-3(1)/(3)A(1) and B-1(1)/(1)A(1) Renner Teller pairs, respectively, in the C-2v symmetry. Considering only the allowed singlet singlet transitions at the ground state equilibrium geometry, the lowest energy transitions found to have transition moment values of 0.65 D and 0.48 D for H2F+ and H2Cl+, respectively, appearing in the far UV region. Conical intersections take place during the symmetrical stretching of two H-Cl bonds in the chloronium ion for the first two pairs of excited states (1(3)A(2)/1(3)B(1) and 1(1)A(2)/1(1)B(1)) in the C-2v symmetry. This intersection may initiate pre-dissociation from the upper bound adiabatic (1)A '' state to the lower repulsive (1)A '' state in the C, symmetry. Fluoronium ion is expected to dissociate via a single electronic state due to the absence of such intersection.

• 出版日期2010-3