A theoretical study of the electronic spectroscopy of the SiF3 radical

A recent vacuum-UV fluorescence spectrum of SiF4 [H. Biehl, K.J. Boyle, D.P . Seccombe, D.M. Smith, R.P. Tuckett, K.R. Yoxall, H. Baumgartel, H.W. Joch ims, J. Chem. Phys. 107 (1997) 720] has yielded information about the decay of electronically excited states of neutral fragments and the parent molec ular cation. Emission in the visible region (lambda > 380 nm) has been obse rved for an excitation energy of 13.0 eV with a lifetime of 3.9 ns, but the emitter was not assigned. Ab initio CASSCF calculations show that the obse rved emission is due to the (A) over tilde (2)A(1)-(X) over tilde (2)A(1) t ransition in the SiF3 radical. The experimental lifetime, however, is too s hort to be attributed to this radiative process. We suggest that the lifeti me is dominated by rapid internal conversion of SiF3 (A) over tilde (2)A(1) into high vibrational levels of the ground state. (C) 2001 Elsevier Scienc e B.V. All rights reserved.