MOLPRO

6 PROGRAM CONTROL 36
Certain important input data can be passed to the program using variables. For instance, occupancy
patterns, symmetries, number of electrons, and multiplicity can be defined in this way
(see section 8.8 for more details). This allows the quite general use of procedures. For example,
assume the following procedure has been defined at the top of the input:
PROC MRCI
IF (INTDONE.EQ.0) INT
IF (SCFDONE.EQ.0) THEN
SCF
ENDIF
MULTI
CI
ENDPROC
This procedure can be used for a calculation of a vertical ionization potential of H 2 O as follows:
R=1 ANG !Set bond distance
THETA=104 DEGREE !Set bond angle
BASIS=VTZ
GEOMETRY
O
H1,O,R
H2,O,R,H1,THETA
ENDG
HF
MRCI
EH2O=ENERGY
!Define basis set
!Geometry input block
!Z-matrix
!End of geometry input
!Compute mrci energy of water using defaults
!save mrci energy in variable EH2O
SET,NELEC=9 !Set number of electrons to 9
SET,SYMMETRY=2 !Set wavefunction symmetry to 2
HF
MRCI
!Compute mrci energy of H2O+ (2B2 state)
IPCI=(ENERGY-EH2O)*TOEV
!Compute MRCI ionization potential in eV
Note: At present, all variables are global, i.e., variables are commonly known to all procedures
and all variables defined in procedures will be subsequently known outside the procedures as
well. The reason is that procedures are included into the internal input deck at the beginning of
the job and not at execution time; for the same reason, variable substitution of procedure names
is not possible, e.g. one cannot use constructs like
method=scf
$method
!this does not work!
6.9 Text cards (TEXT)
TEXT,xxxxxx
will just print xxxxxx in the output. If the text contains variables which are preceded by a dollar
($), these are replaced by their actual values, e.g.