Calculations of nonlinear wave-packet interferometry signals in the pump-probe limit as tests for vibrational control over electronic excitation transfer

Abstract

The preceding paper [J. D. Biggs and J. A. Cina, J. Chem. Phys. 131, 224101 (2009)] (referred to here as Paper 1), describes a strategy for externally influencing the course of short-time electronic excitation transfer (EET) in molecular dimers and observing the process by nonlinear wave-packet interferometry (nl-WPI). External influence can, for example, be exerted by inducing coherent intramolecular vibration in one of the chromophores prior to short-pulse electronic excitation of the other. Within a sample of isotropically oriented dimers having a specified internal geometry, a vibrational mode internal to the acceptor chromophore can be preferentially driven by electronically nonresonant impulsive stimulated Raman (or resonant infrared) excitation with a short polarized "control" pulse. A subsequent electronically resonant polarized pump then preferentially excites the donor, and EET ensues. Paper 1 investigates control-pulse-influenced nl-WPI as a tool for the spectroscopic evaluation of the effect of coherent molecular vibration on excitation transfer, presenting general expressions for the nl-WPI difference signal from a dimer following the action of a control pulse of arbitrary polarization and shape. Electronic excitation is to be effected and its interchromophore transfer monitored by resonant pump and probe "pulses," respectively, each consisting of an optical-phase-controlled ultrashort pulse-pair having arbitrary polarization, duration, center frequency, and other characteristics. Here we test both the control strategy and its spectroscopic investigation-with some sacrifice of amplitude-level detail-by calculating the pump-probe difference signal. That signal is the limiting case of the control-influenced nl-WPI signal in which the two pulses in the pump pulse-pair coincide, as do the two pulses in the probe pulse-pair. We present calculated pump-probe difference signals for (1) a model excitation-transfer complex in which two equal-energy monomers each support one moderately Franck-Condon active intramolecular vibration; (2) a simplified model of the covalent dimer dithia-anthracenophane, representing its EET dynamics following selective impulsive excitation of the weakly Franck-Condon active nu(12) anthracene vibration at 385 cm(-1); and (3) a model complex featuring moderate electronic-vibrational coupling in which the site energy of the acceptor chromophore is lower than that of the donor.

Quantum state and process tomography of energy transfer systems via ultrafast spectroscopy

“…Hence, a highlight of the TD/TB signal is that it is determined exclusively by the dynamics of the single-exciton manifold. Scenarios where the TD/TB configuration is preferred compared to the PE are excitonic systems coupled to highly non-Markovian baths (25)(26)(27)(28). iv.…”

A witness for coherent electronic vs vibronic-only oscillations in ultrafast spectroscopy

“…16,17,36,42,46,47 We assume that the doubly excited state has no binding energy, V f (x, y) = V 10 (x, y) + V 01 (x, y), and that the carrier frequency of both pulses is ω p ≡ ω C . The parameters for the calculations are listed in Table I.…”

“…12-15 and 61) and have been shown to nontrivially affect energy transfer too. [16][17][18][19][20][21][22][23][24][25] Although there is additional evidence to support the interpretation that the oscillations are due to electronic states (beating frequencies and comparison with all-atom simulations 8,26 ), unambiguous tools to experimentally unravel the nature of these oscillations are required. A big step has been the observation that, under weak coupling to vibrations and negligible coherence transfer processes, electronic coherences imply oscillations in off-diagonal peaks of rephasing 2D-ES and in diagonal peaks of their non-rephasing counterparts, 27 whereas general vibronic coherences show up as oscillations in any region of either spectra.…”

Weak‐Field, Multiple‐Cycle Carrier Envelope Phase Effects in Laser Excitation

“…The effects of such relative phases are well known and have been employed, for example, for quantum control in a one-photon transition, [22][23][24] or more general wave-packet interferometric excitations. [25][26][27][28] Let us next take a different approach and introduce new basis states as [Eqs. (9) and (10)]:…”