title: Ab Initio Multiple Spawning Photochemical Dynamics of DMABN Using GPUs.
abstract: The ultrafast decay dynamics of 4-(N,N-dimethylamino)benzonitrile (DMABN) following photoexcitation was studied with the ab initio multiple spawning (AIMS) method, combined with GPU-accelerated linear-response time-dependent density functional theory (LR-TDDFT). We validate the LR-TDDFT method for this case and then present a detailed analysis of the first ≈200 fs of DMABN excited-state dynamics. Almost complete nonadiabatic population transfer from S2(the initially populated bright state) to S1takes place in less than 50 fs, without significant torsion of the dimethylamino (DMA) group. Significant torsion of the DMA group is only observed after the nuclear wavepacket reaches S1and acquires locally excited electronic character. Our results show that torsion of the DMA group is not prerequisite for nonadiabatic transitions in DMABN, although such motion is indeed relevant on the lowest excited state (S1).
authors.affiliation: Department of Chemistry and the PULSE Institute, Stanford University , Stanford, California 94305, United States.|SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors.forename: Basile F E
authors.initials: BF
authors.lastname: Curchod
authors.affiliation: Department of Chemistry and the PULSE Institute, Stanford University , Stanford, California 94305, United States.|SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors.forename: Aaron
authors.initials: A
authors.lastname: Sisto
authors.affiliation: Department of Chemistry and the PULSE Institute, Stanford University , Stanford, California 94305, United States.|SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors.forename: Todd J
authors.identifier: http://orcid.org/0000-0002-4798-8947
authors.initials: TJ
authors.lastname: Martínez