RESONANCE CAPTURE OF ELECTRONS BY MOLECULES OF SUBSTITUTED PYRANS

Negative-ion mass spectrometry in the mode of resonance capture of ele ctrons and photoelectron spectroscopy in combination with quantum-chem ical calculations showed that the formation of the resonance states of negative molecular ions in the reaction of electrons with molecules o f substituted pyrans in the ultraviolet optical excitation energy regi on occurs according to the mechanism of intershell Feshbach resonance with the consecutive excitation of an electron from several higher occ upied MO to one vacant MO. In a low-energy region, the resonance at 1. 4 eV is a resonance of form and the resonance at 3-4 eV is the usual e lectron exciting Feshbach resonance with a parent triplet state (pi,pi )(3). The one and the same vacant pi*(CC) MO is ''active'' in all the resonances mentioned.