Theoretical study of the excitation spectrum of azomethane

Szalay, Péter G.; Aquino, Adélia J. A.; Barbatti, Mario; Lischka, Hans

doi:10.1016/j.chemphys.2010.08.013

Cited by 15 publications

(12 citation statements)

References 61 publications

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“…One-photon excitation to the n−π* state is symmetry forbidden in trans-azomethane. As shown by Szalay et al, 61 the 1 B g n−π* state can borrow intensity from a 1 B u Rydberg state as low as 6.4 eV through the A u CNNC dihedral angle vibrational mode. The intensity borrowing spectrum calculated by Szalay et al is in accordance with the Herzberg−Teller effect 62 since, for the C 2h point group, the inner product of the A u and the B g irreducible representations is the B u representation.…”

Section: Excitation Energy and Conical Intersectionmentioning

confidence: 91%

Interfacing the Ab Initio Multiple Spawning Method with Electronic Structure Methods in GAMESS: Photodecay oftrans-Azomethane

Gaenko¹,

DeFusco

Varganov

et al. 2014

J. Phys. Chem. A

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This work presents a nonadiabatic molecular dynamics study of the nonradiative decay of photoexcited trans-azomethane, using the ab initio multiple spawning (AIMS) program that has been interfaced with the General Atomic and Molecular Electronic Structure System (GAMESS) quantum chemistry package for on-the-fly electronic structure evaluation. The interface strategy is discussed, and the capabilities of the combined programs are demonstrated with a nonadiabatic molecular dynamics study of the nonradiative decay of photoexcited trans-azomethane. Energies, gradients, and nonadiabatic coupling matrix elements were obtained with the state-averaged complete active space self-consistent field method, as implemented in GAMESS. The influence of initial vibrational excitation on the outcome of the photoinduced isomerization is explored. Increased vibrational excitation in the CNNC torsional mode shortens the excited state lifetime. Depending on the degree of vibrational excitation, the excited state lifetime varies from ∼60-200 fs. These short lifetimes are in agreement with time-resolved photoionization mass spectroscopy experiments.

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Section: Excitation Energy and Conical Intersectionmentioning

confidence: 91%

Interfacing the Ab Initio Multiple Spawning Method with Electronic Structure Methods in GAMESS: Photodecay oftrans-Azomethane

Gaenko¹,

DeFusco

Varganov

et al. 2014

J. Phys. Chem. A

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“…In the limit of a very fast decay of the time-correlation function, the overlap function reduces to Eq. (15) and the line has a Gaussian shape. Employing molecular dynamics simulations of chromophores within non-polar fluids, Saven and Skinner [10] showed that Kubo's model works well in these two limits, but cannot produce accurate line shapes in intermediary regimes.…”

Section: Nuclear-ensemble Approximationmentioning

confidence: 99%

“…If DE 0;n R ð Þ is approximately constant over R, then d n and e n in Eq. (15) can be obtained by comparison with Eq. (14) and be defined in terms of and of x j , D nj , and dE 0;n ¼ DE 0;n À DE a 0;n as:…”

Section: Overlap Function: Approximationmentioning

confidence: 99%

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Spectrum simulation and decomposition with nuclear ensemble: formal derivation and application to benzene, furan and 2-phenylfuran

2012

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A formal derivation of the nuclear-ensemble method for absorption and emission spectrum simulations is presented. It includes discussions of the main approximations employed in the method and derivations of new features aiming at further developments. Additionally, a method for spectrum decomposition is proposed and implemented. The method is designed to provide absolute contributions of different classes of states (localized, diffuse, charge-transfer, delocalized) to each spectral band. The methods for spectrum simulation and decomposition are applied to the investigation of UV absorption of benzene, furan, and 2-phenylfuran, and of fluorescence of 2-phenylfuran

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“…84 The ADC(2) scheme is therefore often preferred in studies that go beyond the vertical excitation picture. 82,83,[85][86][87][88] As in our previous work, 82,83 the information about the vibrational structure associated with the electronic transitions was obtained from the linear vibronic coupling (LVC) model. 89,90 This model allows the adiabatic (O 0-0 ) transition energies to be determined and the Franck-Condon spectrum for a given excited state to be constructed, once the linear vibrational coupling constants have been evaluated.…”

Section: Computational Detailsmentioning

confidence: 99%

Excited electronic states of thiophene: high resolution photoabsorption Fourier transform spectroscopy and ab initio calculations

Holland

Trofimov

Seddon

et al. 2014

Phys. Chem. Chem. Phys.

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The recently introduced synchrotron radiation-based Fourier transform spectroscopy has been employed to study the excited electronic states of thiophene. A highly resolved photoabsorption spectrum has been measured between ∼5 and 12.5 eV, providing a wealth of new data. High-level ab initio computations have been performed using the second-order algebraic-diagrammatic construction (ADC(2)) polarization propagator approach, and the equation-of-motion coupled-cluster (EOM-CC) method at the CCSD and CC3 levels, to guide the assignment of the spectrum. The adiabatic energy corrections have been evaluated, thereby extending the theoretical study beyond the vertical excitation picture and leading to a significantly improved understanding of the spectrum. The low-lying π→π* and π→σ* transitions result in prominent broad absorption bands. Two strong Rydberg series converging onto the X(~)(2)A2 state limit have been assigned to the 1a2→npb1(1)B2 and the 1a2→nda2(1)A1 transitions. A second, and much weaker, d-type series has been assigned to the 1a2→ndb1(1)B2 transitions. Excitation into some of the Rydberg states belonging to the two strong series gives rise to vibrational structure, most of which has been interpreted in terms of excitations of the totally symmetric ν4 and ν8 modes. One Rydberg series, assigned to the 3b1→nsa1(1)B1 transitions, has been identified converging onto the Ã(2)B1 state limit, and at higher energies Rydberg states converging onto the B(~)(2)A1 state limit could be identified. The present spectra reveal highly irregular vibrational structure in certain low energy absorption bands, and thus provide a new source of information for the rapidly developing studies of excited state non-adiabatic dynamics and photochemistry.

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Theoretical study of the excitation spectrum of azomethane

Cited by 15 publications

References 61 publications

Interfacing the Ab Initio Multiple Spawning Method with Electronic Structure Methods in GAMESS: Photodecay oftrans-Azomethane

Interfacing the Ab Initio Multiple Spawning Method with Electronic Structure Methods in GAMESS: Photodecay oftrans-Azomethane

Spectrum simulation and decomposition with nuclear ensemble: formal derivation and application to benzene, furan and 2-phenylfuran

Excited electronic states of thiophene: high resolution photoabsorption Fourier transform spectroscopy and ab initio calculations

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