Infrared spectra of C2H4 dimer and trimer

TL;DR

This study presents the first rotationally resolved infrared spectra of ethylene trimer and provides detailed structural insights into ethylene dimers and trimers using advanced spectroscopic techniques.

Contribution

It reports the first rotationally resolved spectrum of C2H4 trimer and supports specific structural models for ethylene clusters.

Findings

First spectrum of C2H4 trimer obtained.

Supports D2d dimer and C3h/C3 trimer structures.

Dimer spectrum in nu9 region shows perturbations.

Abstract

Spectra of ethylene dimers and trimers are studied in the nu11 and (for the dimer) nu9 fundamental band regions of C2H4 (~2990 and 3100 cm-1) using a tunable optical parametric oscillator source to probe a pulsed supersonic slit jet expansion. The deuterated trimer has been observed previously, but this represents the first rotationally resolved spectrum of (C2H4)3. The results support the previously determined cross-shaped (D2d) dimer and barrel-shaped (C3h or C3) trimer structures. However, the dimer spectrum in the nu9 fundamental region of C2H4 is apparently very perturbed and a previous rotational analysis is not well verified.