Jump to main content
Jump to site search

Issue 24, 2015
Previous Article Next Article

OH-stretch overtone of methanol: empirical assignment using a two temperature technique in a supersonic jet

Author affiliations

Abstract

This paper describes a novel approach for empirical lower state assignments in complex high resolution ro-vibrational overtone spectra of molecules with low rotational constants and complex intramolecular dynamics. Methanol, CH3OH, was chosen as a representative of such molecules – it is an asymmetric top with two non-hydrogen nuclei and hindered internal rotation leading to dense and disordered rotational structure of vibrational overtone bands. We report the first rotationally resolved methanol spectra of the OH-stretch overtone 2ν1 band using sub-Doppler diode laser spectroscopy in a supersonic jet, and describe how the combination of two temperature analysis (TTA) and analysis by ground state combination differences (GSCDs) is used to reliably identify spectral lines that originate from lowest rotational states. In the first step of the analysis, the TTA was utilized to obtain a set of possible rotational assignments for each spectral line using the line intensity variation between two different temperatures in the supersonic jet (13, and 56 K respectively). Thereafter, the GSCDs were used to confirm specific lower state assignment for those spectral lines that have been identified to have low rotational ground states by the TTA. We show that the TTA pre-selection leads to fast and reliable confirmation by GSCDs and avoids false assignments due to accidental GSCD matches. The procedure yields an important subset of reliably assigned spectral lines in the complex ro-vibrational structure that provides a convenient starting point for subsequent application of traditional spectral analysis techniques.

Graphical abstract: OH-stretch overtone of methanol: empirical assignment using a two temperature technique in a supersonic jet

Back to tab navigation

Supplementary files

Publication details

The article was received on 23 Jan 2015, accepted on 03 May 2015 and first published on 11 May 2015


Article type: Paper
DOI: 10.1039/C5CP00425J
Author version available: Download Author version (PDF)
Citation: Phys. Chem. Chem. Phys., 2015,17, 15710-15717
  •   Request permissions

    OH-stretch overtone of methanol: empirical assignment using a two temperature technique in a supersonic jet

    V. Svoboda, V. Horká-Zelenková, J. Rakovský, P. Pracna and O. Votava, Phys. Chem. Chem. Phys., 2015, 17, 15710
    DOI: 10.1039/C5CP00425J

Search articles by author

Spotlight

Advertisements