Chemical timing. 2. The picosecond dynamics of intramolecular vibrational redistribution in S1 p-difluorobenzene

The dynamics of conformational isomerization in flexible biomolecules. I. Hole-filling spectroscopy of N-acetyl tryptophan methyl amide and N-acetyl tryptophan amide

“…In this sense, the present reliance of the experiment on collisional cooling to probe intramolecular dynamics bears some resemblance with the chemical timing experiments of Parmenter and co-workers. [23][24][25][26][27] The cooling collisions complicate the theoretical modeling of the hole-filling experiment because the temperature and collision frequency are changing as the expansion occurs.…”

Complex and Sustained Quantum Beating Patterns in a Classic IVR System: The 3151 Level in S1 p-Difluorobenzene

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Among the levels studied, one found at 2068 cm -1 above the S 1 origin has attracted particular interest. [10][11][12][13] This level is usually labelled the 3 1 5 1 level, 15 and involves excitation of one quantum in mode 3 (CF stretching) and one quantum in mode 5 (ring breathing).…”

Picosecond time-resolved photoelectron spectroscopy as a means of gaining insight into mechanisms of intramolecular vibrational energy redistribution in excited states

“…Zewail and coworkers attributed the discrepancy between their work and that of Parmenter and coworkers to the difference in temperature of the sample. In our own work we used a jet-cooled sample and deduced an IVR lifetime of 26 ps from picosecond time-resolved photoelectron spectra [12,32], using the kinetic formalism developed by Parmenter [13]. It will be clear from Table 2 that the lifetimes deduced by Parmenter's group and our group are in reasonable agreement, but that they are in severe disagreement with the observations of Zewail and coworkers.…”

“…In these experiments the IVR process will cause different vibrational levels in the ground state (dispersed fluorescence) or ion (photoelectron spectroscopy) to be populated, and thus a Franck-Condon fingerprint of the contributing dark states can be observed which is time-dependent. This time dependence can be used to extract an IVR lifetime or rate [13], and in principle the dark states populated as a function of time can be identified from their Franck-Condon fingerprint. In such experiments scientists must take great care to understand exactly what they have prepared, what their measurements imply, and how they can be realistically compared with other measurements.…”