Stimulated emission spectroscopy of van der Waals vibrational levels of glyoxal(Xtilde;thinsp;1Ag)sdot;Ar

摘要

Stimulated emission spectroscopy was used to study the electronic ground state vibrationndash;rotation levels of van der Waals complexes generated in a supersonic beam. This technique can be used to study all the vibrational levels with nonvanishing Franckndash;Condon factors from the electronic excited states with 0.04 cmminus;1resolution. Five van der Waals vibrational levels in theXtilde; state were directly observed in the stimulated emission spectra and were assigned to the fundamental and first overtone levels of the two Arsdot;glyoxal bending modes and the stretching fundamental level. In addition, the rotational constants and the structure were determined for both theAtilde; andXtilde; state complex, together with the vibrational term values and the widths of single rotational levels of the three glyoxal vibrations in the glyoxalsdot;Ar complex, the Cndash;C stretchv4=1, the CH wagv8=1 and the OCC bendv5=1 level.