Experimental Linestrengths of Far-Infrared Pure Rotational Transitions of Ozone

Abstract

The pure rotational b-type spectrum of nitrogen pressure-broadened ozone lines has been measured in the region from 25 to 95 cm −1 with a Bruker IFS 120 HR interferometer. Linestrengths for mostly isolated rR Ka lines have been experimentally determined for K a = 3 to 10 with a precision better than 2% for most of the transitions. These data are the first experimental linestrengths for pure rotational transitions of an asymmetric top. An elaborate procedure has been developed to monitor and evaluate the particle density of ozone even with foreign gas pressure-broadening, employing a combination of absolute pressure data and spectroscopic measurements. From the experimental linestrengths. the permanent electric dipole moment was calculated to be 0.53592(65) D. which deviates from the value determined from Stark measurements by 0.49%. This corresponds to a systematic error of 0.98% for the combined linestrength data. Thus, all systematic error sources for the theoretical and experimental linestrength determinations including the uncertainty in pressure (06-0.9%) are below 1% .