Matrix isolation Fourier transform infrared (MI/FT-IR) data has been présented that documents the presence of discrete conformers in an argon matrix for a series of ketones. The distribution of conformers in the matrix was related to the structure of the molecule, in that rigid structures (i.e., small rings, bicyclic systems, and unsaturated systems) displayed simple carbonyl absorption patterns relative to those of their less rigid counterparts. Also, conformer isolation was seen for halosubstituted ketones. These results are in agreement with previous findings concerning the vapor-phase (VP) spectra of these molecules.
W. M. Coleman and Bert M. Gordon, "Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part VIII," Appl. Spectrosc. 42, 304-309 (1988)