Nonpolar nitrous oxide dimer: Observation of combination bands of (14N2O)2 and (15N2O)2 involving the torsion and antigeared bending modes

Abstract

Spectra of the nonpolar nitrous oxide dimer in the region of the N(2)O ν(1) fundamental band were observed in a supersonic slit-jet apparatus. The expansion gas was probed using radiation from a quantum cascade or a tunable diode laser, with both lasers employed in a rapid-scan signal averaging mode. Four bands were observed and analyzed: new combination bands involving the intermolecular conrotation of the monomers (A(g) antigeared bend) for ((14)N(2)O)(2) and ((15)N(2)O)(2), the previously reported torsional combination band for ((14)N(2)O)(2) with improved signal-to-noise ratio, and the same torsional combination band for ((15)N(2)O)(2). The resulting frequencies for the intermolecular antigeared mode are 96.0926(1) and 95.4912(1) cm(-1) for ((14)N(2)O)(2) and ((15)N(2)O)(2), respectively. This is the third of the four intermolecular frequencies which has now been measured experimentally, the others being the out-of-plane torsion and the geared bend modes. Our experimental results are in good agreement with two recent high level ab initio theoretical calculations.

Communication: Spectroscopic observation of the O-bonded T-shaped isomer of the CO-CO2 dimer and two of its intermolecular frequencies

“…This equal and opposite change in A almost certainly indicates the presence of an a-type Coriolis interaction between these two excited intermolecular states, similar, for example, to that noted previously for the N 2 O dimer. 16 We found that inclusion of an interaction parameter equal to 0.575 cm −1 effectively removes the large changes in A, while giving a fit which is equal in quality to the original one. This interaction parameter implies a value of 0.72 for the dimensionless Coriolis constant, ζ a .…”

“…1. In both cases, the structures have C 2v symmetry with the CO monomer aligned along the C 2 symmetry axis, and the absence of odd K a ′′ -values is explained by the nuclear spin statistics of the equivalent 16 O atoms of the CO 2 .…”

New infrared bands of nonpolar OCS dimer and experimental frequencies for two intermolecular modes

“…Similar conclusions have been drawn for (N 2 O) 2 . 27 What about the two remaining binary combination bands? According to the theoretical values listed in Table I, the antigeared combination band is predicted to be around 2123 cm −1 , where we do not have diode laser coverage.…”

Infrared spectra of the Ne2–N2O, Ar2–N2O trimers

“…Spectra were recorded using a previously described pulsed supersonic jet apparatus at the University of Calgary [31][32][33][34] together with a new Daylight Solutions quantum cascade laser which operates from about 2140-2265 cm À1 [35]. The expansion gas was a dilute mixture (%0.8%) of N 2 O in neon or argon.…”