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Title: Nonadiabatic excited-state molecular dynamics: On-the-fly limiting of essential excited states

The simulation of nonadiabatic dynamics in extended molecular systems involving hundreds of atoms and large densities of states is particularly challenging. Nonadiabatic coupling terms (NACTs) represent a significant numerical bottleneck in surface hopping approaches. Rather than using unreliable NACT cutting schemes, here we develop “on-the-fly” state limiting methods to eliminate states that are no longer essential for the non-radiative relaxation dynamics as a trajectory proceeds. Here, we propose a state number criteria and an energy-based state limit. The latter is more physically relevant by requiring a user-imposed energy threshold. For this purpose, we introduce a local kinetic energy gauge by summing contributions from atoms within the spatial localization of the electronic wavefunction to define the energy available for upward hops. The proposed state limiting schemes are implemented within the nonadiabatic excited-state molecular dynamics framework to simulate photoinduced relaxation in poly-phenylene vinylene (PPV) and branched poly-phenylene ethynylene (PPE) oligomers for benchmark evaluation.
ORCiD logo [1] ;  [2] ;  [3] ; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Skolkovo Inst. of Science and Technology, Moscow (Russian Federation)
  3. National Univ. of Quilmes, Buenos Aires (Argentina)
Publication Date:
Report Number(s):
Journal ID: ISSN 0301-0104
Grant/Contract Number:
AC52-06NA25396; PICT-2010-2375
Accepted Manuscript
Journal Name:
Chemical Physics
Additional Journal Information:
Journal Volume: 481; Journal Issue: C; Journal ID: ISSN 0301-0104
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA); National Scientific and Technical Research Council (CONICET); National Promotion Agency Scientific and Technological (ANPCyT)
Country of Publication:
United States
74 ATOMIC AND MOLECULAR PHYSICS; fewest switches surface hopping; NA-ESMD; state reduction; local kinetic energy; poly-phenylene vinylene; poly-phenylene ethynylene
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1396782