Accidental Interaction in the Torsional Spectrum of Singly Deuterated Hydrogen Peroxide HOOD

TL;DR

This study extends the infrared spectra of singly deuterated hydrogen peroxide (HOOD) into the submm range, deriving precise molecular parameters and analyzing accidental torsional interactions with minimal interaction constants.

Contribution

It provides the first detailed analysis of accidental torsional interactions in HOOD using extensive spectral data and a simplified interaction model.

Findings

Over 1500 torsional transitions assigned between 6 and 120 cm$^{-1}$

Accidental interactions characterized by only two constants

Determined $K_a$- and $J$-dependence of torsional splitting

Abstract

We extended previously recorded infrared spectra of singly deuterated hydrogen peroxide (HOOD) to the submm-wavelength region and derived accurate molecular parameters and a semi-empirical equilibrium structure. In total, more than 1500 ro-torsional HOOD transitions have been assigned between 6 and 120 cm$^{-1}$. We succeeded to analyze the accidental interaction between the torsional sub-states by measuring several perturbed transitions. In addition to the set of Watsonian parameters for each tunneling component, only two interaction constants were required to describe the spectrum. The $K_a$- and $J$-dependance of the torsional splitting could be determined also for the perturbed states.