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Photophysics of fulvene under the non-resonant stark effect: shaping the conical intersection seam

We introduce a mechanistic strategy to control the excited state lifetime of fulvene based on shaping the topography of an extended seam of intersection with the non-resonant dynamic Stark effect. Fulvene has a very short excited state lifetime due to an energetically accessible seam of intersection which lies along the methylene torsion coordinate, and the initial decay occurs at the seam segment around the planar conical intersection structure. We have followed a three-step approach to simulate the control. First, we have calculated the effect of a non-resonant electric field on the potential energy surface at the ab initio level, including the field in a self-consistent way. The relative energy of the planar segment of the seam is increased by the non-resonant field. In the second step we simulate the control carrying out MCTDH quantum dynamics propagations under a static non-resonant field to derive the main control mechanisms. At moderately intense fields (ε ≤ 0.03 a.u.) the decay is faster as compared to the field free case because the vibrational overlap between the excited and ground state vibrational functions is increased. However, at more intense fields (ε = 0.04 a.u.) the planar conical intersection is energetically inaccessible and the decay occurs at a slower time scale, at the segment of the seam with more twisted geometries. In the third step, the control over the dynamics is exerted with a non-resonant dynamic field. The acceleration of the decay due to the improved vibrational overlap does not occur, but the decay can be made slower with a dynamic field of 0.08 a.u. The results show the viability of our approach to control the photophysics shaping the topology of the conical intersection seam, and they prove that the extended nature of the seam is crucial for simulating and understanding the control

This work has been supported by grants CTQ2008-06696 and CTQ2011-26573 from the Spanish Ministerio de Ciencia e Innovacion (MICINN) and Ministerio de Economia y Competividad (MINECO), respectively, SGR0528 from the Catalan Agencia de Gestio d’Ajuts Universitaris i de Recerca (AGAUR), UNGI08-4E-003 from MICINN and the European Fund for Regional Development, and the Xarxa de Referencia en Quimica Teorica i Computacional de Catalunya from AGAUR. S.R.-B. thanks the MICINN for grant BES-2009-029177

© Faraday Discussions, 2013, vol. 163, p. 497-512

Royal Society of Chemistry (RSC)

Author: Ruiz-Barragán, Sergi
Blancafort San José, Lluís
Date: 2013
Abstract: We introduce a mechanistic strategy to control the excited state lifetime of fulvene based on shaping the topography of an extended seam of intersection with the non-resonant dynamic Stark effect. Fulvene has a very short excited state lifetime due to an energetically accessible seam of intersection which lies along the methylene torsion coordinate, and the initial decay occurs at the seam segment around the planar conical intersection structure. We have followed a three-step approach to simulate the control. First, we have calculated the effect of a non-resonant electric field on the potential energy surface at the ab initio level, including the field in a self-consistent way. The relative energy of the planar segment of the seam is increased by the non-resonant field. In the second step we simulate the control carrying out MCTDH quantum dynamics propagations under a static non-resonant field to derive the main control mechanisms. At moderately intense fields (ε ≤ 0.03 a.u.) the decay is faster as compared to the field free case because the vibrational overlap between the excited and ground state vibrational functions is increased. However, at more intense fields (ε = 0.04 a.u.) the planar conical intersection is energetically inaccessible and the decay occurs at a slower time scale, at the segment of the seam with more twisted geometries. In the third step, the control over the dynamics is exerted with a non-resonant dynamic field. The acceleration of the decay due to the improved vibrational overlap does not occur, but the decay can be made slower with a dynamic field of 0.08 a.u. The results show the viability of our approach to control the photophysics shaping the topology of the conical intersection seam, and they prove that the extended nature of the seam is crucial for simulating and understanding the control
This work has been supported by grants CTQ2008-06696 and CTQ2011-26573 from the Spanish Ministerio de Ciencia e Innovacion (MICINN) and Ministerio de Economia y Competividad (MINECO), respectively, SGR0528 from the Catalan Agencia de Gestio d’Ajuts Universitaris i de Recerca (AGAUR), UNGI08-4E-003 from MICINN and the European Fund for Regional Development, and the Xarxa de Referencia en Quimica Teorica i Computacional de Catalunya from AGAUR. S.R.-B. thanks the MICINN for grant BES-2009-029177
Format: application/pdf
ISSN: 1364-5498 (versió paper)
1364-5498 (versió electrònica)
Document access: http://hdl.handle.net/10256/11476
Language: eng
Publisher: Royal Society of Chemistry (RSC)
Collection: MEC/PN 2009-2011/CTQ2008-06696
MICINN/PN 2012-2014/CTQ2011-26573
AGAUR/2009-2014/2009 SGR-528
MEC/2008/UNGI08-4E-003
Reproducció digital del document publicat a: http://dx.doi.org/10.1039/c3fd20155d
Articles publicats (D-Q)
Is part of: © Faraday Discussions, 2013, vol. 163, p. 497-512
Rights: Tots els drets reservats
Subject: Fotoquímica
Photochemistry
Hidrocarburs
Hydrocarbons
Dinàmica molecular
Molecular dynamics
Title: Photophysics of fulvene under the non-resonant stark effect: shaping the conical intersection seam
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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