bdfopt

Introduction

Geometry optimiser of BDF package. Two optimizers can be used:

1. Interface to 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

2. Original optimizer in BDF developed by Dr. Yong Zhang.

This BDFOPT module can be used to find minimal points, saddle points and also conical intersection points, when combined with TD-DFT and RESP modules. For details of the interface, see bdfopt/, module/bdfopt_mod.F90,dlfind_module.F90, sys_util/bdf_dlfind_util.F90 for interface.

Current limitations

This preliminary version has several limitations:

0. Optimization in C(1) symmetry has some problems near minimum.

1. Change of symmetry during optimization is not correctly handled for excited state optimization, because the correct input file needs to be prepared.

2. Since RESP only support nonrelativistic calculations currently, spin-free X2C based approach can not be used in optimization [to be changed in future].

Examples

Ground-state opt

$COMPASS    
Title
 CH2 Molecule test run, cc-pvqz
Basis
 3-21g
# cc-pvdz
Geometry
O       0.00000000     -0.00000000      0.00174418
H      -0.78045951      0.00000000     -0.10962269
H       0.78045951      0.00000000     -0.10962269
End geometry
Check
Skeleton
$END

$bdfopt
$end

$XUANYUAN
$END

$SCF
RHF
$END

$resp
geom
norder
1
method
1
$end

Excited state opt

$COMPASS    
Title
 CH2 Molecule test run, cc-pvqz
Basis
 3-21g
Geometry
 O  0.000000    0.000000    0.243991
 H  0.000000    1.178727   -0.45964
 H  0.000000   -1.178727   -0.45964
End geometry
Check
Skeleton
$END

$bdfopt
$end

$XUANYUAN
$END

$SCF
RHF
$END

$tddft
imethod
1
itda
0
idiag
1
istore
1
iexit
1
crit_e
1.d-8
crit_vec
1.d-6
$end

$resp
geom
norder
1
method
2
states
1
1 4 1
nfiles
1
$end

Conical intersection with pp-TDA

$COMPASS    
Title
 CH2 Molecule test run, cc-pvqz
Basis
 sto-3g
# 6-31GP
Geometry
 C                  0.00000000   -0.67759997   -0.00000000
 H                  0.92414474   -1.21655197    0.00000000
 H                 -0.92414474   -1.21655197    0.00000000
 C                 -0.00000000    0.67759997   -0.00000000
 H                 -0.92414474    1.21655197    0.00000000
 H                  0.92414474    1.21655197   -0.00000000
End geometry
Check
Skeleton
$END

$bdfopt
solver
0
imulti
1
icoord
0
$end

$XUANYUAN
$END

$SCF
RHF
charge
2
spin
1
$END

$tddft
imethod
4
itda
1
idiag
1
istore
1
iexit
2
crit_e
1.d-8
crit_vec
1.d-6
$end

$resp
geom
norder
1
method
2
states
2
1 1 1
1 1 2
nfiles
1
$end


$resp
quad
fnac
double
norder
1
method
2
pairs
1
1 1 1 1 1 2
nfiles
1
$end

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