Structure and Vibrations of the CF_3NO Molecule in the Ground and Lowest Excited Electronic States:A Test of ab Initio Methods

摘要

Equilibrium geometries,harmonic vibrational frequencies,and barriers to internal rotation of the CF_3NO molecule in the ground singlet (S_0) and lowest excited triplet (T_1) and singlet (S_1) electronic states are calculated using various ab initio techniques and compared with the experimental data.The sensitivity of the results to the choice of atomic orbital basis set,in particular,to the presence of f-symmetry functions,and to the dynamical correlation treatment is analyzed.Anharmonic vibrational frequencies and dipole moment of the CF_3NO molecule in the ground state are computed.The results of all approaches employed are in good agreement with each other and with available experimental data.Conclusions concerning the accuracy of different methods are drawn.