Isomerization around C–C and C–O bonds in 1-propanol: Collisional relaxation in supersonic jets and selective IR photo-isomerization in cryogenic matrices

FTIR/PCA study of propanol in argon matrix: The initial stage of clustering and conformational transitions

“…The general trend in the assignment of the H-bond bands (3000-3600 cm -1 ) in simple alcohols, most frequently met in the literature, looks like -"the lower band frequency the higher aggregate". In many cases this is confirmed by proper quantum chemistry calculations [4,5,8,12]. Following this scheme, the sharp peaks of the highest frequencies, i.e., at 3660 and 3643 cm -1 (Figs.…”

“…However several negative peaks appearing in the dynamic spectra at 3660, 3643, 3564, 3553 cm -1 that correspond to νO-H band group of monomer and most probably mixed dimer and also at some parts of νC-H band group. These negatives peaks are caused by the decrease of monomeric and dimeric species with increasing temperature (see discussion below) and by the conformational transitions of 1-propanol molecules [4]. The processing of experimental data using PCA was realized in the following steps.…”

“…We have considered only the so-called Gt conformer of 1-propanol which was found to be the lowest energy conformer at both DFT and coupled cluster levels [4,8,20]. We did not consider any vibrational frequency scaling.…”

“…The most significant results on this field have been obtained using the vibrational spectroscopy (FTIR absorption and Raman) together with trapping/isolation in various cryogenic matrices [4][5][6][7][8][9][10][11][12][13][14]. This is mainly because the spectral acquisition carried out on isolated clusters at very low temperatures causes the appearance of narrow peaks with minimal band overlapping.…”

“…This is mainly because the spectral acquisition carried out on isolated clusters at very low temperatures causes the appearance of narrow peaks with minimal band overlapping. Hence, it provides the possibility to study the spectral properties of individual clusters of different sizes and even various molecular conformers within those clusters [4,5,8]. Thus the studies of small H-bond clusters of different size and conformations having the possibility to manipulate them and to resolve these effects in spectra experimentally can provide extremely valuable information for further progress in this field.…”