Intermediate photofragment distributions as probes of non-adiabatic dynamics at conical intersections: application to the Hartley band of ozone

Picconi, David; Grebenshchikov, Sergy Yu.

doi:10.1039/c5cp04564a

Cited by 9 publications

(8 citation statements)

References 48 publications

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“…Evaluation of the photodissociation matrix element γ(ǫ, k f , n f |E k , τ ) requires numerical solution of the Schrödinger equation with the (generally three-dimensional) potential energy surfaces of the dissociative electronic states of CO + 2 . While the nuclear dynamics for the photofragment distributions can be efficiently calculated using iterative methods, [90][91][92] construction of the multidimensional potential energy surfaces of many densely spaced (and possibly interacting) electronic states in the energy range illustrated in Fig. 2 is a true challenge.…”

Section: Discussionmentioning

confidence: 99%

Quantum mechanical study of the attosecond nonlinear Fourier transform spectroscopy of carbon dioxide

Grebenshchikov,

Carbajo

2021

Preprint

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Attosecond nonlinear Fourier transform (NFT) pump probe spectroscopy is an experimental technique which allows investigation of the electronic excitation, ionization, and unimolecular dissociation processes. The NFT spectroscopy utilizes ultrafast multiphoton ionization in the extreme ultraviolet spectral range and detects the dissociation products of the unstable ionized species. In this paper, a quantum mechanical description of NFT spectra is suggested, which is based on the second order perturbation theory in molecule-light interaction and the high level ab initio calculations of CO 2 and CO + 2 in the Franck-Condon zone. The calculations capture the characteristic features of the available experimental NFT spectra of CO 2 . Approximate analytic expressions are derived and used to assign the calculated spectra in terms of participating electronic states and harmonic photon frequencies. The developed approach provides a convenient framework within which the origin and the significance of near harmonic and non-harmonic NFT spectral lines can be analyzed.The framework is scalable and the spectra of di-and triatomic species as well as the dependences on the control parameters can by predicted semi-quantitatively.

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Section: Discussionmentioning

confidence: 99%

Quantum mechanical study of the attosecond nonlinear Fourier transform spectroscopy of carbon dioxide

Grebenshchikov,

Carbajo

2021

Preprint

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“…The quantum mechanical calculations of the rovibrational photofragment distributions in the electronic channel H + pyrrolyl( 2 A 2 ), diabatically correlating with the state 1 1 A 2 (πσ * ), are performed using the projection method of Balint-Kurti and coworkers, 16,17 which is formulated here in the time-independent framework. 15,18,19 The partial photodissociation cross section for the formation of pyrrolyl in a final vibrational state n is given by: 15,17 σ…”

Section: A Quantum Mechanical Calculationsmentioning

confidence: 99%

“…The convolution of the spectral functions in Eq. (15), is valid for the Green's functions as well: 21…”

Section: B Overlap Integral-based Mapping Calculations Of the Photofmentioning

confidence: 99%

Photodissociation dynamics in the first absorption band of pyrrole. II. Photofragment distributions for the 1A2(πσ*)←X̃1A1(ππ) transition

Picconi

Grebenshchikov

2018

The Journal of Chemical Physics

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The analysis of the total kinetic energy release (TKER) of the photofragments pyrrolyl + H-atom formed in the photodissociation of pyrrole in the low-lying state A(πσ*) is presented. The TKER distributions contain complementary and often more precise information on the fragmentation process than the broad diffuse absorption spectra. The distributions are calculated quantum mechanically for the diabatic state A(πσ*) either isolated or coupled to the ground electronic state at an exit channel conical intersection. The calculations use the novel ab initio quasi-diabatic potential energy matrix constructed in the work of Picconi and Grebenshchikov [J. Chem. Phys. 148, 104103 (2018)]. The approximate overlap integral-based adiabatic mapping approach is introduced with which the quantum mechanical TKER distributions can be efficiently and accurately reproduced. Finally, the calculated TKERs are compared with the experimental results. The main features of the measured vibrationally resolved distributions are reproduced, and the spectral peaks are assigned and interpreted in detail.

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“…Located in the exit dissociation channel, these CIs strongly affect the molecular photoreactivity and, in particular, influence the vibrational state distributions and the kinetic energy release of the photofragments. 37,38 In a recent quantum mechanical study, we discovered their fingerprints in the absorption spectra as strongly asymmetric Fano resonances. 39 With the aim to understand the dynamics at these exit channel CIs, the weakest portion of the first absorption band, located below 5.7 eV, has been extensively studied in the frequencyand time domain by many experimental and theoretical groups.…”

Section: Introductionmentioning

confidence: 99%

Photodissociation dynamics in the first absorption band of pyrrole. I. Molecular Hamiltonian and the Herzberg-Teller absorption spectrum for the A21(πσ*)←X̃1 A1(ππ) transition

Picconi

Grebenshchikov

2018

The Journal of Chemical Physics

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This paper opens a series in which the photochemistry of the two lowest πσ* states of pyrrole and their interaction with each other and with the ground electronic state X̃ are studied using ab initio quantum mechanics. New 24-dimensional potential energy surfaces for the photodissociation of the N-H bond and the formation of the pyrrolyl radical are calculated using the multiconfigurational perturbation theory (CASPT2) for the electronic states X̃(ππ), 1A(πσ*), and 1B(πσ*) and locally diabatized. In this paper, the ab initio calculations are described and the photodissociation in the state 1A(πσ*) is analyzed. The excitation 1 A←X̃ is mediated by the coordinate dependent transition dipole moment functions constructed using the Herzberg-Teller expansion. Nuclear dynamics, including 6, 11, and 15 active degrees of freedom, are studied using the multi-configurational time-dependent Hartree method. The focus is on the frequency resolved absorption spectrum as well as on the dissociation time scales and the resonance lifetimes. Calculations are compared with available experimental data. An approximate convolution method is developed and validated, with which absorption spectra can be calculated and assigned in terms of vibrational quantum numbers. The method represents the total absorption spectrum as a convolution of the diffuse spectrum of the detaching H-atom and the Franck-Condon spectrum of the heteroaromatic ring. Convolution calculation requires a minimal quantum chemical input and is a promising tool for studying the πσ* photodissociation in model biochromophores.

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Intermediate photofragment distributions as probes of non-adiabatic dynamics at conical intersections: application to the Hartley band of ozone

Cited by 9 publications

References 48 publications

Quantum mechanical study of the attosecond nonlinear Fourier transform spectroscopy of carbon dioxide

Quantum mechanical study of the attosecond nonlinear Fourier transform spectroscopy of carbon dioxide

Photodissociation dynamics in the first absorption band of pyrrole. II. Photofragment distributions for the 1A2(πσ*)←X̃1A1(ππ) transition

Photodissociation dynamics in the first absorption band of pyrrole. I. Molecular Hamiltonian and the Herzberg-Teller absorption spectrum for the A21(πσ*)←X̃1 A1(ππ) transition

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