Quantum time evolution of vibrational states in curve-crossing problems

Broeckhove, J.; Feyen, Bart; Lathouwers, L.; Arickx, F.; Leuven, P. Van

doi:10.1016/s0009-2614(90)87187-v

Cited by 41 publications

(20 citation statements)

References 25 publications

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“…The wavepacket propagation is done by splitoperator technique [46,47] as implemented by Broeckhove et al [48] for the curve-crossing problems. A brief outline of the method is given below.…”

Section: Wave Packet Propagation On the Coupled Potential Energy Surfmentioning

confidence: 99%

Manifestation of conical intersections in resonance Raman intensities

Chowdary¹,

Umapathy²

2009

J Raman Spectroscopy

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This paper deals with the manifestations of conical intersections (CIs), unequivocal spectroscopic signatures of which are still elusive, in the resonance Raman intensities. In particular, the results of our calculations on the 'two state-two vibrational mode' and the 'two state-three vibrational mode' models are presented. The models comprise two excited states of different spatial symmetry, one bright and one dark, which are coupled by a nontotally symmetric mode while the energy gap between them is tuned by one/two totally symmetric modes. Time dependent theory for vibronically coupled states is employed for the calculation and analysis of Raman excitation profiles (REPs). The manifestation of intersections in REPs is studied by extensive model calculations and the results of two specific models are presented. The feasibility of using REPs to probe the role of CIs in polyatomic systems is ascertained by multimode calculations on two polyatomic systems viz., pyrazine and trans-azobenzene. The study also notes the importance of the pump excitation wavelength dependence in a femtosecond time-resolved experiment probing the intersection-induced nonadiabatic dynamics.

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Section: Wave Packet Propagation On the Coupled Potential Energy Surfmentioning

confidence: 99%

Manifestation of conical intersections in resonance Raman intensities

Chowdary¹,

Umapathy²

2009

J Raman Spectroscopy

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“…Calculated quantum dynamical pump-probe traces and the corresponding power spectra for J 0 under mesobatic conditions in the Rb 2 A b system. An initially Gaussian wave packet at rest at the inner turning point of the A state is propagated [18] and probed at the outer turning point of either the A (lower) or b (upper) state. Other employed parameters correspond to those of the experiments.…”

mentioning

confidence: 99%

Bound-Bound State Quantum Wave Packet Dynamics in the Intermediate Coupling Range: TheA Σu+1(0u+

2003

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The real-time quantum dynamics of a wave packet confined to two coupled bound states at intermediate interaction strength is probed by experiment and calculations on the A1Sigma(+)(u) approximately b (3)II(u) system in Rb2 molecules. The general dynamics consists of rapid spreading out over the whole phase space. Particular conditions exist, however, under which the initial wave packet motion separates into two mesobatic trajectories with distinct frequencies. These diabatic or adiabatic hybrid trajectories are analogous to those responsible for longevity resonances in bound-unbound systems.

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“…The wavepacket propagation is done by the split-operator technique 54,55 as implemented by Broechkove et al 72 for curve crossing problems.…”

Section: Multimode Vibronic Coupling Model Of S 1 -S 2 Conical Intersmentioning

confidence: 99%

Ultrafast dynamics and photochemistry of π–π* excited trans‐azobenzene—a comprehensive analysis of resonance Raman intensities

Chowdary

Umapathy

2008

J Raman Spectroscopy

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Azobenzene and its derivatives have widely been recognized as systems with potential applications such as optical switching elements, and the mechanism of trans-cis photoisomerization, which is the basis for all these applications, has long been sought. The long-standing controversy on the relaxation mechanism of p-p * (S 2 ) excited trans-azobenzene (TAB) is addressed in this paper. The role of S 1 -S 2 intersection and the possible involvement of a third state in the S 2 photochemistry are investigated. The excited state structure and dynamics of TAB are extracted by modeling the Raman excitation profiles (REPs) of the S 1 and S 2 states and the absorption spectrum of TAB by Heller's time-dependent formalism. The REPs of S 2 are modeled in the single resonant state approximation by explicitly including the eight most Franck-Condon (FC) active modes. The obtained NN and CN bond lengths of S 2 and the intial dynamics in these coordinates following photoexcitation to S 2 are in agreement with recent theoretical calculations. The structural parameters of S 1 are obtained by exploiting the nature of interference in the REPs of S 1 . From these parameters a three-mode-two-state vibronic coupling model, based on harmonic diabatic potentials and linear coupling, is formulated to study the S 2 -S 1 internal conversion dynamics. The resultsindicate that the S 1 -S 2 intersection is not directly accessible within electronic dephasing time of S 2 to cause significant population decay from S 2 to S 1 . The current conception of p-p * relaxation mechanisms in TAB is reviewed and revised on the basis of our observations and also from recently reported results of time-resolved and theoretical studies. The role of a third state (S 3 ), which appears to be an integral part of in the relaxation mechanism of S 2 , is pointed out and the feasibility of two competing relaxation pathways for S 2 state is identified. One is the direct rotationless S 2 -S 1 (C 2h ) internal conversion and the other is S 2 -S 3 internal conversion along rotational pathway followed by a branching of the S 3 population to S 0 and S 1 .

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Quantum time evolution of vibrational states in curve-crossing problems

Cited by 41 publications

References 25 publications

Manifestation of conical intersections in resonance Raman intensities

Manifestation of conical intersections in resonance Raman intensities

Bound-Bound State Quantum Wave Packet Dynamics in the Intermediate Coupling Range: TheA Σu+1(0u+

Ultrafast dynamics and photochemistry of π–π* excited trans‐azobenzene—a comprehensive analysis of resonance Raman intensities

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