State-selected and state-to-state photoionization study of trichloroethene using the two-color infrared-vacuum ultraviolet scheme.

By employing the two-color infrared (IR)-vacuum ultraviolet (VUV) laser photoionization (PI) schemes, we have determined the C[Single_Bond]H stretching frequencies ν[sub 12]=3097.7 cm[sup -1] for trichloroethene (CHCl==CCl[sub 2]) and ν[sub 12][sup +]=3066 cm[sup -1] for CHCl==CCl[sub 2][sup +]. On the basis of the IR-VUV-pulsed field ionization-photoelectron (PFI-PE) measurement, the ratio of the state-to-state PI cross section for CHCl==CCl[sub 2][sup +](ν[sub 12][sup +]=1)←CHCl==CCl[sub 2](ν[sub 12]=1) to that for the formation of the ground state ion from the ground state neutral is determined to be 0.24. The VUV-PI efficiency (PIE) spectrum for CHCl==CCl[sub 2] and IR-VUV-PIE spectrum for CHCl==CCl[sub 2](ν[sub 12]=1) show that the state-to-state PI cross section for the formation of CHCl==CCl[sub 2][sup +] in the ground state from CHCl==CCl[sub 2](ν[sub 12]=1) is ≈0.006 that from CHCl==CCl[sub 2] in its ground state. As expected, the IR-VUV-PIE onset for CHCl==CCl[sub 2](ν[sub 12]=1) exhibits less hot-band tailing than the VUV-PIE onset for supersonically cooled CHCl==CCl[sub 2]. After taking into account the ν[sub 12] frequency, the ionization energy values for CHCl==CCl[sub 2] determined based on the IR-VUV-PIE and VUV-PFI-PE measurements are found to be in excellent agreement. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]