MOLPRO

24 THE CLOSED SHELL CCSD PROGRAM 185
24.6.2 Single-reference correlation treatments for N 2 F 2
***,N2F2 CIS GEOMETRY (C2h)
rnn=1.223,ang
!define N-N distance
rnf=1.398,ang
!define N-F distance
alpha=114.5;
!define FNN angle
geometry={N1
N2,N1,rnn
F1,N1,rnf,N2,alpha
F2,N2,rnf,N1,alpha,F1,180}
basis=vtz
!cc-pVTZ basis set
$method=[hf,cisd,ccsd(t),qcisd(t),bccd(t)] !all methods to use
do i=1,#method
!loop over requested methods
$method(i)
!perform calculation for given methods
e(i)=energy
!save energy in variable e
enddo
!end loop over methods
table,method,e
!print a table with results
title,Results for n2f2, basis=$basis !title of table
http://www.molpro.net/info/current/examples/n2f2_ccsd.com
This calculation produces the following table:
Results for n2f2, basis=VTZ
METHOD E E-ESCF
CISD -308.4634948 -0.78283137
BCCD(T) -308.6251173 -0.94445391
CCSD(T) -308.6257931 -0.94512967
QCISD(T) -308.6274755 -0.94681207
24.7 Saving the density matrix
DM[,record.ifil];
The effective first order density matrix is computed an stored in record record on file ifil. This
currently works for closed-shell MP2, QCISD, and QCISD(T). See also NATORB. Note that this
is much more expensive than a simple energy calculation, since the response equations have
to be solved. Note: CCSD first order properties without orbital relaxation contribution can be
computed using
ccsd
expec,dm
The orbital relaxation can be included using
ccsd
core,0
expec,relax,dm
Currently, this works only without core, i.e., CORE,0 is required.