A General Approach for Calculating Strongly Anharmonic Vibronic Spectra with a High Density of States: The X̃2B1 ← X̃1A1 Photoelectron Spectrum of Difluoromethane

Petrenko, Taras; Rauhut, Guntram

doi:10.1021/acs.jctc.7b00468

Cited by 18 publications

(17 citation statements)

References 64 publications

(148 reference statements)

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“…This method was found to be very robust, even for very high state densities, see for example the spectrum of CH2F 2. 295 Quite recently, this approach has been extended for the calculation of Herzberg-Teller terms.…”

Section: B Anharmonic Vibrational Spectramentioning

confidence: 99%

The Molpro quantum chemistry package

Werner

Knowles

Manby

et al. 2020

The Journal of Chemical Physics

Self Cite

931

737

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Molpro is a general purpose quantum chemistry software package with a long development history. It was originally focused on accurate wavefunction calculations for small molecules but now has many additional distinctive capabilities that include, inter alia, local correlation approximations combined with explicit correlation, highly efficient implementations of single-reference correlation methods, robust and efficient multireference methods for large molecules, projection embedding, and anharmonic vibrational spectra. In addition to conventional input-file specification of calculations, Molpro calculations can now be specified and analyzed via a new graphical user interface and through a Python framework.

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Section: B Anharmonic Vibrational Spectramentioning

confidence: 99%

The Molpro quantum chemistry package

Werner

Knowles

Manby

et al. 2020

The Journal of Chemical Physics

Self Cite

931

737

View full text Add to dashboard Cite

show abstract

“…In order to calculate a vibronic spectrum, one needs to consider the transformation between two electronic potential energy surfaces (PESs). The hypersurfaces may be substantially anharmonic, making accurate classical calculations beyond a few atoms impossible [29][30][31][32]. In order to introduce our approach, we begin by assuming that the two PESs are harmonic (i.e.…”

Section: Toc Graphicmentioning

confidence: 99%

Quantum Algorithm for Calculating Molecular Vibronic Spectra

Sawaya

Huh

2019

J. Phys. Chem. Lett.

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We present a quantum algorithm for calculating the vibronic spectrum of a molecule, a useful but classically hard problem in chemistry. We show several advantages over previous quantum approaches: vibrational anharmonicity is naturally included; after measurement, some state information is preserved for further analysis; and there are potential error-related benefits. Considering four triatomic molecules, we numerically study truncation errors in the harmonic approximation. Further, in order to highlight the fact that our quantum algorithm's primary advantage over classical algorithms is in simulating anharmonic spectra, we consider the anharmonic vibronic spectrum of sulfur dioxide. In the future, our approach could aid in the design of materials with specific lightharvesting and energy transfer properties, and the general strategy is applicable to other spectral calculations in chemistry and condensed matter physics. TOC GraphicCalculating the absorption spectrum of molecules is a common and important problem in theoretical chemistry, as it aids both the interpretation of experimental spectra and the a priori design of molecules with particular optical properties prior to performing a costly laboratory synthesis. Further, in many molecular clusters and systems, absorption and emission spectra of molecules are required for calculating energy transfer rates [1]. The widespread use of mature software that solves the vibronic problem is one indication of its relevance to chemistry [2][3][4][5].Many quantum algorithms have been proposed for practical problems in chemistry, chiefly for solving the fermionic problem of determining the lowest-energy configuration of N e electrons, given the presence of a set of clamped atomic nuclei [6][7][8][9][10][11][12][13][14]. However, for many chemical problems of practical interest, solving the groundstate electronic structure problem is insufficient. To calculate exact vibronic spectra, for instance, an often combinatorially scaling classical algorithm must be imple-

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“…Analog [12,13] and digital [14,15,21] quantum algorithms have been proposed to simulate molecular vibronic spectra. Although the quantum phase estimation algorithm-based digital approach [14,15] considers anharmonicity (which is difficult to simulate classically [22][23][24][25]), it requires a fault-tolerant quantum computer to output satisfactory results. Although it may be possible to create another digital quantum protocol, that is suitable for noisy intermediate-scale quantum devices, such as the variational quantum eigensolver [15,26,27], the non-Condon problem may still require significant resources.…”

Section: Introductionmentioning

confidence: 99%

Analog quantum simulation of non-Condon effects in molecular spectroscopy

Jnane,

Sawaya,

Peropadre

et al. 2020

Preprint

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A General Approach for Calculating Strongly Anharmonic Vibronic Spectra with a High Density of States: The X̃²B₁ ← X̃¹A₁ Photoelectron Spectrum of Difluoromethane

Cited by 18 publications

References 64 publications

The Molpro quantum chemistry package

The Molpro quantum chemistry package

Quantum Algorithm for Calculating Molecular Vibronic Spectra

Analog quantum simulation of non-Condon effects in molecular spectroscopy

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