High-Resolution Spectroscopic Investigation of nu16 in trans-1,2-Dichloroethane

Area of Science:

• Molecular Spectroscopy
• Physical Chemistry
• Quantum Mechanics

Background:

• 1,2-dichloroethane is a significant organochlorine compound with complex molecular dynamics.
• Understanding its rovibrational spectra is crucial for identifying molecular structure and interactions.
• Previous analyses lacked detailed rovibrational resolution for specific absorption bands.

Purpose of the Study:

• To perform the first detailed rovibrational analysis of the a-type nu16 absorption band in gaseous trans-1,2-dichloroethane.
• To investigate the spectral characteristics of different isotopomers, including those with chlorine-35 and chlorine-37.
• To analyze nuclear spin statistics and interpret complex spectral features at the band center.

Main Methods:

• Fourier transform interferometry was employed to record the absorption spectrum.
• Experiments were conducted under both room temperature and jet-cooled conditions.
• Rotational analysis was performed on prominent R and P branch structures for specific isotopomers.

Main Results:

• The a-type nu16 absorption band of trans-1,2-dichloroethane was successfully analyzed at 1232 cm-1.
• Detailed rotational analysis was achieved for trans-1,2-12C2H435Cl2 and trans-1,2-12C2H435Cl37Cl isotopomers.
• Complex absorption patterns at the band center were attributed to overlapping Q branches from fundamental and hot bands involving multiple vibrational modes and isotopomers.

Conclusions:

• The study provides a comprehensive rovibrational analysis of the nu16 band, enhancing the understanding of 1,2-dichloroethane's molecular spectroscopy.
• Nuclear spin statistics were discussed, offering insights into the behavior of different isotopomers and isomers.
• The findings contribute to the detailed characterization of molecular vibrations and rotational structures in halogenated hydrocarbons.