Threshold photoelectron studies of isoxazole over the energy range 9.9-30 eV

The threshold photoelectron spectrum of the isoxazole molecule, C3H3NO has been measured over the photon energy range 9.9eV to 30eV with the use of synchrotron radiation. In the 9.9-10.8 eV range, corresponding to photoionization from the highest occupied molecular orbital 3a�(?3), seven well resolved vibrational series have been observed and their modes are tentatively assigned. A strong adiabatic ionization, with an energy of 11.132 ± 0.003eV corresponding to the 2a–�(?2) band, has also been observed. This is followed by a single vibrational series of the vC-H stretching mode. Photoelectron bands in the energy region 13-30 eV have also been identified, some for the first time