This paper reports the first use of radiation derived from a TEA carbon dioxide laser
by nonlinear upshifting techniques (second harmonic generation) in initiating multiphoton
absorption and dissociation. The frequency doubled CO2 laser has frequency
coverage from 2180–1750 cm–1. This frequency region is of importance as it allows
pumping of the fundamental stretching modes of organic carbonyl groups (anhydrides,
acyl chlorides and strained cyclic ketones), inorganic carbonyl groups, and carbontritium
bonds. The laser has been used to excite cyclobutanone in the region of the
carbonyl stretch. Efficient multiphoton absorption and two channel dissociation are
observed. The product array is consistent with that observed upon excitation at 10 μm.