Ab initio-CI study of SCH3 radical: analysis of the Jahn-Teller effect in the ground state

Ab initio structural and vibrational calculations have been performed on th e ground state and first excited state of methylthio-radical. The ground st ate has E symmetry. The relaxation of this C-3 nu structure leads to two C( s)A' and A" structures. The Jahn-Teller effect is quite small (84 cm(-1)) a nd the C(s)A' form is slightly more stable (48 cm(-1)) than the C-s A" one. The vertical transitions, calculated with the configuration interaction, e nable the low-lying states to be described. The potential energy surface, c alculated near the Jahn-Teller point, is very similar to the well-known CH3 O radical one. (C) 2000 Elsevier Science B.V. All rights reserved.