Absorption and Fluorescence Lineshape Theory for Polynomial Potentials

Anda, André; Vico, Luca De; Hansen, Thorsten; Abramavičius, Darius

doi:10.1021/acs.jctc.6b00997

Cited by 33 publications

(34 citation statements)

References 70 publications

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“…47 For more realistic non-harmonic potential energy surfaces, higher order cumulants will contribute to the lineshape. 54,55 The cumulants can be expressed in terms of time-ordered integrals of increasing orders of quantum time-correlation functions C δU of the energy gap fluctuation operator δU . For the second and third order cumulant, we can write…”

Section: A Linear Absorption Spectra In the Cumulant Approachmentioning

confidence: 99%

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Nonlinear Spectroscopy in the Condensed Phase: The Role of Duschinsky Rotations and Third Order Cumulant Contributions

Zuehlsdorff

Hong²,

Shi³

et al. 2020

Preprint

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First-principles modeling of nonlinear optical spectra in the condensed phase is highly challenging because both environment and vibronic interactions can play a large role in determining spectral shapes and excited state dynamics. Here, we compute two dimensional electronic spectroscopy (2DES) signals based on a cumulant expansion of the energy gap fluctuation operator, with a specific focus on analyzing mode mixing effects introduced by the Duschinsky rotation and the role of the third order term in the cumulant expansion for both model and realistic condensed phase systems. We show that for a harmonic model system, the third order cumulant correction captures effects introduced by a mismatch in curvatures of ground and excited state potential energy surfaces, as well as effects of mode mixing. We also demonstrate that 2DES signals can be accurately reconstructed from purely classical correlation functions using quantum correction factors. We then compute nonlinear optical spectra for the Nile red and Methylene blue chromophores in solution, assessing the third order cumulant contribution for realistic systems. We show that the third order cumulant correction is strongly dependent on the treatment of the solvent environment, revealing the interplay between environmental polarization and the electronic-vibrational coupling.

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Section: A Linear Absorption Spectra In the Cumulant Approachmentioning

confidence: 99%

“…with analogous expressions for higher order quantum correlation functions. 54 The second order cumulant contribution g 2 (t) is commonly expressed in terms of the spectral density of system-bath coupling J (ω) by switching into Fourier space and evaluating the time-ordered integrals analytically: 47…”

Section: A Linear Absorption Spectra In the Cumulant Approachmentioning

confidence: 99%

Nonlinear Spectroscopy in the Condensed Phase: The Role of Duschinsky Rotations and Third Order Cumulant Contributions

Zuehlsdorff

Hong²,

Shi³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…Treatment of anharmonic behaviour has been tackled by stochastic environments 29,30 , molecular dynamics simulations [31][32][33] , and by including anharmonicity in the system potential [34][35][36] . In this study we use anharmonic system potentials whilst also including an interacting environment via a) cmlds@leeds.ac.uk b) A.G.Dijkstra@leeds.ac.uk the stochastic Schrödinger equation 22,37,38 .…”

Section: Introductionmentioning

confidence: 99%

“…Anharmonicity and its effects can manifest itself in numerous ways. The shape of the entire potential can be important, as in the case of the Morse potential and generally in the case of polynomial potentials 34 . Additionally, displaced harmonic oscillators that have different curvatures are accredited with giving rise to non-standard spectral features 35,47 .…”

Section: Introductionmentioning

confidence: 99%

Quantum dissipative systems beyond the standard harmonic model: Features of linear absorption and dynamics

Smith

Dijkstra

2019

The Journal of Chemical Physics

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Current simulations of ultraviolet-visible absorption lineshapes, and dynamics of condensed phase systems, largely adopt a harmonic description to model vibrations. Often, this involves a model of displaced harmonic oscillators that have the same curvature. Although convenient, for many realistic molecular systems this approximation no longer suffices. We elucidate non-standard harmonic, and anharmonic effects, on linear absorption and dynamics using a stochastic Schrödinger equation approach to account for the environment. Firstly, a harmonic oscillator model with ground and excited potentials that differ in curvature is utilised. Using this model, it is shown that curvature difference gives rise to an additional sub-structure in the vibronic progression of absorption spectra. This effect is explained, and subsequently quantified, via a derived expression for the Franck-Condon coefficients. Subsequently, anharmonic features in dissipative systems are studied, using a Morse potential, and parameters that correspond to the diatomic molecule H 2 for differing displacements and environment interaction. Lastly using a model potential, the population dynamics and absorption spectra for the stiff-stilbene photoswitch is presented and features are explained by a combination of curvature difference and anharmonicity in the form of potential energy barriers on the excited potential.

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“…54 Furthermore, the log-normal distributions are quite common in nature. 55,56 From a theoretical point of view, different models have been constructed to account for the non-Gaussian effect 12,29,[57][58][59][60][61] and to investigate the spectral line shape of the time evolution of 2DCS. However, so far no systematic study of the effect of dynamics on the 2DCS has been reported for cases where the underlying frequency distribution is skewed.…”

Section: Introductionmentioning

confidence: 99%

Spectral line shapes in linear absorption and two-dimensional spectroscopy with skewed frequency distributions

Farag

Hoenders

Knoester

et al. 2017

The Journal of Chemical Physics

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The effect of Gaussian dynamics on the line shapes in linear absorption and two-dimensional correlation spectroscopy is well understood as the second-order cumulant expansion provides exact spectra. Gaussian solvent dynamics can be well analyzed using slope line analysis of two-dimensional correlation spectra as a function of the waiting time between pump and probe fields. Non-Gaussian effects are not as well understood, even though these effects are common in nature. The interpretation of the spectra, thus far, relies on complex case to case analysis. We investigate spectra resulting from two physical mechanisms for non-Gaussian dynamics, one relying on the anharmonicity of the bath and the other on non-linear couplings between bath coordinates. These results are compared with outcomes from a simpler log-normal dynamics model. We find that the skewed spectral line shapes in all cases can be analyzed in terms of the log-normal model, with a minimal number of free parameters. The effect of log-normal dynamics on the spectral line shapes is analyzed in terms of frequency correlation functions, maxline slope analysis, and anti-diagonal linewidths. A triangular line shape is a telltale signature of the skewness induced by log-normal dynamics. We find that maxline slope analysis, as for Gaussian dynamics, is a good measure of the solvent dynamics for log-normal dynamics.

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Absorption and Fluorescence Lineshape Theory for Polynomial Potentials

Cited by 33 publications

References 70 publications

Nonlinear Spectroscopy in the Condensed Phase: The Role of Duschinsky Rotations and Third Order Cumulant Contributions

Nonlinear Spectroscopy in the Condensed Phase: The Role of Duschinsky Rotations and Third Order Cumulant Contributions

Quantum dissipative systems beyond the standard harmonic model: Features of linear absorption and dynamics

Spectral line shapes in linear absorption and two-dimensional spectroscopy with skewed frequency distributions

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