Gas phase electronic spectra of xylene-water aggregates

J. E. FULKER; A. GUTIÉRREZ-QUINTANILLA; W. A. BROWN; G. A. PINO; A. NIEDOJADLO; J. A. NOBLE; J. HACQUARD

JOURNAL OF MOLECULAR SPECTROSCOPY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2023

0022-2852

Using a jet spectroscopy molecular beam setup, gas phaseelectronic spectra of three xylene isomers (para, metaand ortho) have been collected for the neutral monomerspecies as well as for their clusters with one and two water molecules. Scans at a resolution of ±0.02 nm showeda clear 0-0 transition for each xylene isomer as well asthe vibronic progression. The spectra were assigned withthe help of Franck-Condon factor PGOPHER simulationsfrom theoretical studies at the CAM-B3LYP/aug-cc-pVDZlevel of theory. The vibronic spectra of the xylene·H2Oand xylene·(H2O)2clusters showed broad features between36800-38400 cm−1(260-272 nm) for p- and m-xylene,while the water clusters of o-xylene gave more definedbands. The separation of the vibronic bands in the clustersmirrors the progression of the neutral monomers implyingthat, for the S1 ← S0 transition, it is the same vibrationalmodes that are involved in the monomer as in the clusterswith water. Both the separation and the spectral width ofthe bands can be explained by the calculated differences ingeometries of the clusters in the ground and first electronicexcited states.