Dynamical spectroscopy of many-body interactions. Coherent vibrations and predissociation of I2(B) in solid Kr

Resonant Raman, Hot, and Cold Luminescence of Iodine in Rare Gas Matrixes

“…The first term in parentheses ensures that the RR emission is not included in the hot luminescence, using the previously determined bath correlation function C b (t) which may be approximated as 21 The exponential decay in (eq 7) accounts for predissociation, and the delta function accomplishes the reflection of the spatial distribution from the difference potential. With a choice of a predissociation constant τ ) 4.5 ps, the same as that previously determined through time-domain measurements in solid Kr, 8 the simulated signal reproduces the expected features of the hot luminescence in Xe, as shown in Figure 11. With the same procedure as outlined for Xe, trajectory data previously used for simulations of pump-probe signals in Kr were inverted to reproduce the hot luminescence spectrum in Figure 12.…”

“…This estimate is in good agreement with real time pump probe measurements of the evolving density on the B state, in which the transients are observed to decay in 4.5 ps, determined by predissociation rates. 8 This also clarifies that although the estimate is two orders of magnitude more intense than the RR progression, because the radiative lifetime of the B state is 10 -6 s, we are monitoring a process of rather low quantum yield of 10 -3 . In the absence of predissociation, this hot luminescence would constitute a negligibly small tail of the vibrationally relaxed emission.…”

“…The picosecond time scale dynamics of I 2 (B) isolated in matrixes, and in particular in solid Kr, was analyzed through classical molecular dynamics simulations which were inverted to reproduce the pump-probe observables. 8,9 The same type of simulations are used here, but now we use the classical trajectories to reproduce the hot-luminescence spectrum. We examine the case of solid Xe, using a 512 atom simulation box with molecular iodine introduced in a divacancy of an otherwise perfect fcc lattice.…”

“…] t > 50 fs (8) corresponds to emission from the turnover region. The location of the maximum is sensitive to both the predissociation rate and the choice of the functional form of the transition dipole, as would be expected from the comparison in Figure 10.…”

“…[8][9][10] Complementary to these measurements is the understanding of the frequency domain spectra of the molecule in condensed phases. The most extensive analysis in this context pertains to the resonant Raman (RR) spectra of iodine, which has been investigated in rare gas solids, [11][12][13] in room-temperature liquids, [14][15][16] and in cryogenic liquid Xe.…”