bdfopt
Contents
Introduction
Geometry optimiser of BDF package. This BDFOPT module can be used to find minimal points, saddle points and also conical intersection points. For details of the interface, see bdfopt/, module/bdfopt_mod.F90,dlfind_module.F90, sys_util/bdf_dlfind_util.F90 for interface.
Two optimizers can be used by specifying the solver keyword:
1. [solver=1] Original optimizer in BDF developed by Dr. Yong Zhang using redundant internal coordinates (more efficient!).
2. [solver=0] Interface to the package - DL-FIND. For details, see: http://ccpforge.cse.rl.ac.uk/gf/project/dl-find/
"DL-FIND: An Open-Source Geometry Optimizer for Atomistic Simulations", Johannes Kästner, Joanne M. Carr, Thomas W. Keal, Walter Thiel, Adrian Wander and Paul Sherwood, J. Phys. Chem. A, 2009, 113 (43), 11856-11865. DOI: 10.1021/jp9028968
The optimization information is stored in filename.pes1 [ground state/excited state] or filename.pes2 [conical intersection].
Currently, the following methods are available:
1. HF/MCSCF with GRAD module
2. HF/DFT/TD-DFT with RESP modules
This preliminary version has several limitations:
1. Change of symmetry during optimization is not correctly handled for excited state optimization, because the correct input file needs to be prepared.
2. Conical intersection optimization does not work properly!
3. Since RESP only support nonrelativistic calculations currently, spin-free X2C based approach can not be used in optimization [to be changed in future].
Notice
MCSCF OPT
For MCSCF geometry optimization, SCF module should use keyword maxiter and set maxiter to the number where SCF energy difference is less than 1 a.u., so that MCSCF calculation will pick up moderate guess MOs.
Examples
General keywords
IPRT
SOLVER
=0, DLFIND; =1, BDF optimizer
MAXCYCLE
TOLGRAD
TOLENE
IOPT
Algorithm for optimization, default L-BFGS
ICOORD
Coordinates
IMULTI
multi-state optimization for conical intersection
ILINE
line search