The intramolecular vibrational redistribution (IVR) dynamics following the excitation of a mode in the first electronically excited states of toluene, toluene-d3 and p-fluorotoluene that has predominantly C-CH3 stretching character and an internal energy of ~1200 cm(-1) have been compared using picosecond time-resolved photoelectron imaging spectroscopy as a probe. Temporal changes in the intensities of spectral features in each molecule have enabled IVR lifetimes of 12, 15 and 50 ps, respectively, to be determined. Our measurements show that doorway states are critical in mediating the IVR dynamics in toluene and toluene-d3, and we deduce that these doorway states, which are assigned in the course of this work, are also instrumental in reducing the IVR lifetimes of these molecules relative to p-fluorotoluene.
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http://dx.doi.org/10.1039/c3cp53055h | DOI Listing |
Phys Chem Chem Phys
January 2014
School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK.
The intramolecular vibrational redistribution (IVR) dynamics following the excitation of a mode in the first electronically excited states of toluene, toluene-d3 and p-fluorotoluene that has predominantly C-CH3 stretching character and an internal energy of ~1200 cm(-1) have been compared using picosecond time-resolved photoelectron imaging spectroscopy as a probe. Temporal changes in the intensities of spectral features in each molecule have enabled IVR lifetimes of 12, 15 and 50 ps, respectively, to be determined. Our measurements show that doorway states are critical in mediating the IVR dynamics in toluene and toluene-d3, and we deduce that these doorway states, which are assigned in the course of this work, are also instrumental in reducing the IVR lifetimes of these molecules relative to p-fluorotoluene.
View Article and Find Full Text PDFJ Chem Phys
April 2013
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
We commence by presenting an overview of the assignment of the vibrational frequencies of the toluene molecule in its ground (S0) state. The assignment given is in terms of a recently proposed nomenclature, which allows the ring-localized vibrations to be compared straightforwardly across different monosubstituted benzenes. The frequencies and assignments are based not only on a range of previous work, but also on calculated wavenumbers for both the fully hydrogenated (toluene-h8) and the deuterated-methyl group isotopologue (α3-toluene-d3), obtained from density functional theory (DFT), including artificial-isotope shifts.
View Article and Find Full Text PDFBiochem Biophys Res Commun
April 1989
Department of Medicinal Chemistry, University of Kansas, Lawrence 66045.
Liver microsomes from phenobarbital-induced rats oxidize toluene to a mixture of benzyl alcohol plus o-, m- and p-cresol (ca. 69:31). Stepwise deuteration of the methyl group causes stepwise decreases in the yield of benzyl alcohol relative to cresols (ca.
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