Interpretation of new 13CD3F submillimeter-wave laser lines using high resolution infrared spectroscopy

Abstract

A high resolution infrared spectrum of 13CD3F has been recorded in the wave number region 820–1350 cm−1 which covers four fundamentals ν2(A1), ν3(A1), ν5(E), and ν6(E). All strong and medium strong vibration-rotation lines have been assigned in terms of a model which treats simultaneously these strongly Coriolis coupled four fundamentals. Fifty-nine upper state parameters have been determined with the least squares method including 4390 infrared transitions as data. The standard deviation of the fit obtained is 0.56×10−3 cm−1. Ground state rotational parameters have been determined using ground state combination differences. Due to strong vibration–rotation interactions a large number of normally forbidden transitions have been observed which have allowed an accurate determination of the ground state axial rotational constant A0 and the centrifugal distortion constant DK0. The results of the analyzed infrared spectrum have made it possible to interpret many new laser emission lines from 13CD3F gas optically pumped with a continuously tunable high pressure pulsed CO2 laser. Making use of the coincidence of the 10 μm P and R branches of CO2 with the ν2, ν3, ν5, and ν6 bands, altogether 151 laser lines of 13CD3F between 10 and 61 cm−1 have been observed. These emission lines have been assigned as rotational transitions within the excited vibrational states and the ground vibrational state.