Mid-infrared spectrum of the weakly bound complex CO2–SO2

Abstract

The mid-infrared spectrum of the CO2–SO2 van der Waals complex was measured near the R(0) transition of the asymmetric stretch of the CO2 monomer at 2349.917 cm−1. The spectra were recorded using a molecular beam tunable diode laser spectrometer, in which the injection nozzle was mounted in a position axial to the Herriott multipass cell. The transitions are c-type, in agreement with spin statistical analysis. Transitions originating from levels with odd Ka in the vibrational ground state are absent from the spectrum. The main spectroscopic constants are ν0 = 2349.6159(1) cm−1, A″ = 5544.98(40) MHz, B″ = 1510.034(37) MHz, C″ = 1489.402(36) MHz, = 4.578(16) kHz, A′ = 5524.58(63) MHz, B′ = 1508.28(14) MHz, C′ = 1488.42(21) MHz, and = 4.07(78) kHz. The spectral assignment was confirmed by microwave-infrared double resonance experiments using several known a-type microwave transitions of the complex.