Vibrational coherence of I2 in solid Kr

Abstract

Time-resolved coherent anti-Stokes Raman scattering, with a resolution of 20 fs, is used to prepare a broadband vibrational superposition on the ground electronic state of I2 isolated in solid Kr. The coherent evolution of a packet consisting of nu=1-6 is monitored for as many as 1000 periods, allowing a precise analysis of the material response and radiation coherence. The molecular vibrations are characterized by omega(e)=211.330(2) cm(-1), omega(e)x(e)=0.6523(6) cm(-1), omega(e)y(e)=2.9(1) x 10(-3) cm(-1); the dephasing rates at 32 K range from 110 ps for nu=1 to 34 ps for nu=6, with nu dependence: gamma(nu)=8.5 x 10(-3)+4.9 x 10(-4)nu2+2.1 x 10(-6)nu4 ps(-1). The signal amplitude is also modulated at omega(q)=41.56(3) cm(-1); which can be interpreted as coupling between the molecule and a local mode. The surprising implication is that this resonant local mode is decoupled from the lattice phonons, a finding that cannot be rationalized based on a normal-mode analysis.

Vibrational relaxation and dephasing of Rb2 attached to helium nanodroplets

“…More recently, dephasing times as well as relaxation rates have been studied extensively by the groups of Apkarian and Schwentner by means of femtosecond spectroscopy of the vibrational dynamics of halide molecules isolated in cryogenic rare-gas matrices [32][33][34][35][36][37]. Seminal work on time-resolved measurements of the dissipative fluid dynamics in bulk He-II has been performed using femtosecond pump-probe spectroscopy of triplet He * 2 excimers created inside He-II [38].…”

Simulation of vibrational dephasing in liquid water using the semiclassical Liouville method

“…Further, the semiclassical Liouville method allows a direct solution of the off-diagonal density matrix element using semiclassical dynamics and trajectory ensembles evolving under the full many-body quantum state-dependent potentials without making further approximations such as cumulant expansions. We have previously applied this approach to simulating the vibrational dephasing of ground electronic state I 2 in a cryogenic Kr matrix [10], and obtained excellent agreement with time-resolved CARS experiments on the system by Apkarian and coworkers [12,13]. In this Letter, we extend the method to the treatment of high-frequency OH vibrations in water at room temperature.…”

“…(12). Results for T = 150 and 298 K are shown, and compared with the result obtained using a cumulant expansion [1] of the quantity and the transition frequency correlation function shown in Figure 2.…”

Quantum Computing and Control by Optical Manipulation of Molecular Coherences: Towards Scalability

“…Indeed, a second PhD thesis was completed on this theme, by H. Seferyan. 6 One of the approaches is collaborative, designed to couple an optical STM with ultrafast NLO. This effort remains in the stage of instrumental development.…”

“…In a set of studies on the ground electronic state of molecular iodine isolated in rare gas matrices, we have generated the most comprehensive data base of vibrational dephasing in the solid state, in Ar, 4' s and in Kr,6 " 89 for v = I through v = 19,' and for T = 2.6 K to 32 K.' 0 These studies are testing grounds for theories on the subject, and we have provided one of the more crucial analysis of the role of vacancy imperfections and thermal phonons in inducing dephasing. ", 2 Vibrational decoherence in the ground electronic state of iodine can be classified as the weak coupling regime, where dephasing is dominated by Raman scattering of phonons, and for v -I the molecule may oscillate for 10 3 periods prior to damping.…”