TY - JOUR

T1 - p-cresol quantum-classical photodynamics, photostatic UV, IR and Raman spectra

AU - Pomogaev, V.

AU - Bocharnikova, E.

AU - Avramov, P.

AU - Tchaikovskaya, O.

N1 - Export Date: 01 November 2025; Cited By: 1; Correspondence Address: V. Pomogaev; Laboratory of Photophysics and Photochemistry of Molecules, Department of Physics, National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050, Russian Federation; email: valienpo@yandex.ru; CODEN: JMOSB

PY - 2025/11/5

Y1 - 2025/11/5

N2 - A joint theoretical and experimental study of photoinduced physicochemical and thermodynamic properties of p-cresol was performed using conventional quantum-mechanical approaches and hybrid quantum-classical methodologies combined with the experimental optical absorption and fluorescent spectroscopy. The CCSD, CC2, MP2 and DFT methods as well as the EoM-CCSD, ADC(2)-MP2 and TD-DFT extensions to electron excitations were involved for optimizations and vertical electron transitions in the isolated p-cresol molecule and continuum implicit solvent model. The absorption and fluorescence spectra of the p-cresol in water were measured experimentally to be used as a reference. Static optical spectra were obtained as the statistically averaged electronic states of instantaneous vibrational conformers fluctuating on quantum-classical molecular dynamical trajectories due to combinations of classical forces with quantum gradient and embedding electrostatic potential fitting with point atomic charges. The excited dissipative crossing potential energy surfaces were defined through conical intersection searches and non-adiabatic molecular dynamics simulations using mixed-reference spin-flip with trajectory surface hopping for photodynamic propagation. Conical intersection points were considered for direct transitions from the lowest excited state to the ground state, as well as for two-stage transitions from the second excited state through a lower-lying level to the unexcited electronic structure. The electronic types of excited states at their intersections and key points on photodynamic trajectories were revealed using electron density differences and Dyson's molecular orbitals based on the extended Koopmans' theorem, whereas canonical molecular orbitals were applied for conventional quantum-mechanical methods. Swift O-H deprotonation through the |π→σOH*〉 transition was demonstrated using both conical intersection and photodynamic simulations. © 2025 Elsevier B.V., All rights reserved.

AB - A joint theoretical and experimental study of photoinduced physicochemical and thermodynamic properties of p-cresol was performed using conventional quantum-mechanical approaches and hybrid quantum-classical methodologies combined with the experimental optical absorption and fluorescent spectroscopy. The CCSD, CC2, MP2 and DFT methods as well as the EoM-CCSD, ADC(2)-MP2 and TD-DFT extensions to electron excitations were involved for optimizations and vertical electron transitions in the isolated p-cresol molecule and continuum implicit solvent model. The absorption and fluorescence spectra of the p-cresol in water were measured experimentally to be used as a reference. Static optical spectra were obtained as the statistically averaged electronic states of instantaneous vibrational conformers fluctuating on quantum-classical molecular dynamical trajectories due to combinations of classical forces with quantum gradient and embedding electrostatic potential fitting with point atomic charges. The excited dissipative crossing potential energy surfaces were defined through conical intersection searches and non-adiabatic molecular dynamics simulations using mixed-reference spin-flip with trajectory surface hopping for photodynamic propagation. Conical intersection points were considered for direct transitions from the lowest excited state to the ground state, as well as for two-stage transitions from the second excited state through a lower-lying level to the unexcited electronic structure. The electronic types of excited states at their intersections and key points on photodynamic trajectories were revealed using electron density differences and Dyson's molecular orbitals based on the extended Koopmans' theorem, whereas canonical molecular orbitals were applied for conventional quantum-mechanical methods. Swift O-H deprotonation through the |π→σOH*〉 transition was demonstrated using both conical intersection and photodynamic simulations. © 2025 Elsevier B.V., All rights reserved.

KW - Conical intersection

KW - Electronic densities

KW - MRSF-TDDFT

KW - Nonadiabatic photodynamic

KW - p-cresol

KW - Statistical optical spectra

KW - Density functional theory

KW - Electron transitions

KW - Electronic density of states

KW - Electronic states

KW - Electronic structure

KW - Excited states

KW - Fluorescence

KW - Ground state

KW - Molecular dynamics

KW - Quantum theory

KW - CCSD

KW - Electronic density

KW - Non-adiabatic

KW - Optical spectrum

KW - P-cresol

KW - Quantum-classical

KW - Statistical optical spectrum

KW - Molecular orbitals

UR - https://www.mendeley.com/catalogue/181f6931-266e-3829-8259-d53eaaf2df9f/

U2 - 10.1016/j.molstruc.2025.142986

DO - 10.1016/j.molstruc.2025.142986

M3 - статья

VL - 1344

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

SN - 0022-2860

ER -