High-resolution far-infrared synchrotron FTIR spectroscopy and analysis of the $\nu_7$, $\nu_{19}$ and $\nu_{20}$ bands of trioxane

TL;DR

This study used high-resolution synchrotron FTIR spectroscopy to analyze the rovibrational spectra of trioxane's specific bands, achieving precise spectral line assignments and deriving accurate molecular parameters.

Contribution

It provides the first precise determination of Coriolis and $l$-doubling constants for trioxane's bands using advanced spectroscopic techniques and formalism comparisons.

Findings

Over 16,000 spectral lines assigned with high accuracy.

First determination of Coriolis and $l$-doubling constants for these bands.

Comparison of tensorial and Watson formalisms for spectral analysis.

Abstract

Rovibrational bands spectra of three $\nu_{20}$, $\nu_7$ and $\nu_{19}$ bands of 1, 3, 5 -- trioxane (H$_2$CO)$_3$ were recorded in the 50--650 cm$^{-1}$ range using a long path absorption cell coupled to a high resolution Fourier transform spectrometer and synchrotron radiation at the AILES beamline of the SOLEIL synchrotron. More than 16000 lines were assigned with a dRMS better than $0.17\times10^{-3}$ cm$^{-1}$. Two different formalisms (tensorial and Watson) were used to derive accurate rotational and quartic parameters for the three bands and for the first time, a precise determination of Coriolis parameter and $q_+$ $l-$doubling constant for both $\nu_{20}$ and $\nu_{19}$ perpendicular bands was obtained. Last, each set of spectroscopic parameters is compared and discussed between both formalisms.