Ground-state opt

HF with GRAD module

$COMPASS    
Title
 H2O
Basis
 3-21g
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

$grad
$end

HF/DFT with RESP module

$COMPASS    
Title
 H2O
Basis
 3-21g
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

CASSCF with GRAD module

# Yibo Lei, 2021.10.28
#----------------------------------------------------------------------
# Geometric optimization of S0 by SA2-CASSCF(4,4)/6-31G
#

$COMPASS
Title
 C6H6 test run, cc-pvdz
Basis
6-31G
Geometry
C             0.00000373      0.00000493      0.66789017
C            -0.00001203     -0.00000431     -0.66791647
H             0.71651373     -0.53471753      1.31749034
H            -0.71649838      0.53472410      1.31749465
H             0.71707430      0.53383897     -1.31766051
H            -0.71710642     -0.53387717     -1.31763176
End geometry
nosym
norotate
saorb
$END

$bdfopt
iprt
 3
imulti
 0
tolgrad
1.d-4
tolstep
5.d-3
tolene
1.d-5
$end

$XUANYUAN
$END

$SCF
rhf
spin
1
atomorb
$END

$MCSCF
close
 6 
active
 4
actele
 4
spin
 1
symmetry
 1
ROOTPRT
 1
roots
2 2 1
prtcri
0.1
molden
guess
read
thresorb
1.d-5
$END

$grad
nrootgrad
1  
double
maxiter
500
mxiter
200
cutcpmc
1.d-4
$end

Try different solvers

$COMPASS    
Title
 H2O
Basis
 3-21g
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
iprt
1  # print internal coordinates
solver
1 # bdf solver
$end

$XUANYUAN
$END

$SCF
RHF
$END

$grad
$end

Scalar relativistic X2C-HF with GRAD module

$COMPASS
Title
 Geometry optimization by scalar X2C-HF
Basis
 ANO-RCC-VDZ
Geometry
 H    0.000000   0.000000   0.000000
 I    0.000000   0.000000   1.610000
End geometry
$END

$XUANYUAN
scalar
heff
 21
Nuclear
  1
$END

$SCF
 RHF
$END

$grad
$end

$bdfopt
$end

Analytic gradients have been implemented for Heff = 21, 22, and 23. Optimizations with the RESP module and/or by different solvers are also available (see the non-relativistic examples above).