Vibronic structure and rotational spectra of radicals in degenerate electronic state. Case of hydroxymethyl radical and asymmetrically deuterated isotopomers (methoxy isotopomers)

Spin-vibronic structure in the ground X˜ 2E electronic state of methoxy radical is investigated using dispersed florescence (DF) spectroscopic technique via laser excitation of the 3151, 3161, 3141 and 35 vibrational states in the excited A2A electronic state and using the rotationally resolved, stimulated-emission-pumping (SEP) technique with the excitation of specific rotational levels in the 35 and 3141 vibrational states in the intermediate A2A electronic state.;A Hamiltonian is derived for the Jahn-Teller distorted X˜ 2E state of methoxy. The potential energy surface is parameterized up to third order terms in nuclear coordinates. In addition, a semi-quantitative approach is developed to treat high order terms perturbationally. The extended potential was successfully implemented in SOCJT software (Jahn-Teller interaction with spin-orbit coupling) in order to simulate and fit the observed dispersed fluorescence spectra. Particular interest is paid to the X˜2 E vibronic quartet structure, assigned in this work to CH stretch fundamentals, and observed in DF through emission from the A 2A 314 1 level. Unperturbed positions of the symmetric and asymmetric CH stretch fundamentals as well as the value of the coupling constant between them has been derived from the analysis of the band positions and intensities. Analysis of the SEP spectra is used to validate further the symmetry assignment of the lines observed in DF spectrum.;In addition, microwave spectra of the methoxy isotopomers, CHD2 O and CH2DO, in subterahertz frequency region are investigated. For CHD2O 14 rotational transitions are assigned and for CH 2DO 20 rotational transitions are assigned and parameters of the introduced effective Hamiltonian are determined.;A general high throughput spectra simulation and data analysis package, SpecView, has been developed and utilized in the analysis described above. The architecture of the program allows for modeling of the electronic, vibrational or microwave spectra of any molecular system. A number of models, describing a large variety of molecules, diatomic and polyatomic, are included in the standard distribution package. The main program engine encapsulates a large number of commonly used procedures used for the processing of experimental data and various tools for the output of the calculated structures.