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Communication: Smoothing out excited-state dynamics: analytical gradients for dynamically weighted complete active
1Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, USA and SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
The Journal of Chemical Physics
|November 10, 2014
Summary
A new dynamical weight with spline (DWS) scheme resolves discontinuities in molecular excited-state calculations. This method enables accurate ab initio molecular dynamics for complex electronic structures where standard methods fail.
Area of Science:
- Quantum Chemistry
- Computational Chemistry
- Theoretical Chemistry
Background:
- State averaged complete active space self-consistent field (SA-CASSCF) is widely used for excited-state electronic structure.
- SA-CASSCF has limitations, including discontinuities in potential energy surfaces during state crossings.
Purpose of the Study:
- Introduce a new dynamical weight with spline (DWS) scheme.
- Address and remove energy discontinuities in excited-state calculations.
- Enable accurate ab initio molecular dynamics for challenging systems.
Main Methods:
- Developed a novel dynamical weight with spline (DWS) scheme.
- Derived analytical gradients for DWS-CASSCF and other dynamically weighted methods.
- Applied the DWS scheme to mimic SA-CASSCF while resolving discontinuities.
Main Results:
- The DWS scheme effectively removes energy discontinuities caused by unweighted state crossings.
- Analytical gradients for DWS-CASSCF were derived for the first time.
- The new method enables energy-conserving excited-state ab initio molecular dynamics.
Conclusions:
- The DWS scheme offers a robust alternative to SA-CASSCF for excited-state calculations.
- This advancement facilitates more reliable molecular dynamics simulations of electronically complex systems.
- The derived analytical gradients are crucial for accurate dynamics simulations.
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