# Synchrotron-Based High Resolution Far-Infrared Spectroscopy of trans-Butadiene

### Abstract

The high resolution far-infrared spectrum of $trans$-butadiene has been re-investigated by Fourier-transform spectroscopy at two synchrotron radiation facilities, SOLEIL and the Canadian Light Source, at temperatures ranging from 50 to 340 K. Beyond the well-studied bands, two new fundamental bands lying below 1100 cm$^{-1}$, ν10 and ν24, have been assigned using a combination of cross-correlation (ASAP software) and Loomis-Wood type (LWWa software) diagrams. While the ν24 analysis was rather straightforward, ν10 exhibits obvious signs of a strong perturbation, presumably owing to interaction with the dark $v$9+$v$12 state. Effective rotational constants have been derived for both the $v_{10}=1$ and $v_{24}=1$ states. Since only one weak, infrared active fundamental band (ν23) of $trans$-butadiene remains to be observed at high resolution in the far-infrared, searches for the elusive $gauche$ conformer can now be undertaken with considerably greater confidence in the dense ro-vibrational spectrum of the $trans$ form.

Publication
The Journal of Physical Chemistry A
##### Marie-Aline Martin-Drumel
###### Researcher

My research interests focus on molecular spectroscopy of stable molecules and reactive species, and its applications for astrophysics and physical-chemistry.

##### Olivier Pirali
###### Director of Research

My research interests includes high resolution molecular spectroscopy, laboratory astrophysics, and THz generation.