Delayed photoisomerisation of the trans-PSB3 retinal toy model using on-the-fly quantum dynamics

We explore the trans–cis photoisomerisation process in a representative retinal protonated Schiff base known as trans-PSB3, employing the quantum dynamics method direct dynamics variational multiconfigurational Gaussian -DD-vMCG- in full dimensionality, i.e., 36 degrees of freedom on potential energ...

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Detalles Bibliográficos
Autores: Mallo, María, Gómez-Carrasco, Susana, Gómez, Sandra
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/733780
Acceso en línea:https://hdl.handle.net/10486/733780
https://dx.doi.org/10.1039/D5CP02117K
Access Level:acceso abierto
Palabra clave:Electronic states
Excited states
Molecular physics
Quantum chemistry
Química
Descripción
Sumario:We explore the trans–cis photoisomerisation process in a representative retinal protonated Schiff base known as trans-PSB3, employing the quantum dynamics method direct dynamics variational multiconfigurational Gaussian -DD-vMCG- in full dimensionality, i.e., 36 degrees of freedom on potential energy surfaces computed on-the-fly using the SA(2)-CAS(6,6)SCF electronic structure method with the 6-31G basis set. Although the toy molecule has been extensively studied using trajectory methods such as Tully surface hopping and ab initio multiple spawning, our application of the on-the-fly quantum dynamics method DD-vMCG reveals a previously unreported trans–cis isomerisation pathway throughthe S1 electronic state minimum that occurs hundreds of femtoseconds more slowly, despite using the same electronic structure method. This slower timescale and alternative deactivation route can be explained in terms of the accesibility to the conical intersections connecting the ground and the excited state