PNNL

Abstract

The infrared absorption spectrum of tropolone vapor at 25 degrees C, ~0.01 Torr, and 32 m path length has been recorded from 960 to about 700 cm (to the negative one) at a resolution of 0.0025 cm (to the negative one). 29 cold band and hot band spectral tuneling doublets marked by sharp type A or type C Q branch apices protruding from the congested vibration-contortion-rotation absorption profiles are assigned and these, together with the known zero-point splitting Delta-subscript zero, allow 30 vibration-contortion state-specific tunneling splittings to be estimated. The results show that tunneling is strongly quenched when the COH torsional fundamental is excited, or when the 110 cm (to the negative one) OCCO/ring twisting fundamental or its overtones are excited.