Linear reponse calculation: *LINEAR

A  linear response [90, 92] calculation is performed for a given choice of operators, .

.SINGLE   The single residue  of the linear response  function is computed. Residues of a linear response function correspond to transition moments .

.DIPMAG   Sets A and B to angular momentum operators .

.DIPLEN   Sets A and B to dipole operators .

.DIPVEL   Sets A and B to velocity operators .

.SPIN-O   Sets A and B to spin-orbit operators .

.MAXIT  
READ (LUCMDS,*) MAXITP
Maximum number of iterations for solving the linear response eigenvalue equation. Default is 20.

.MAXITO  
READ (LUCMDS,*) MAXITO
Maximum number of iterations in the optimal orbital algorithm  [7]. Default is 5.

.ROOTS  
READ '*',(ROOTS(I) I=1,NSYM)
Number of roots. The line following this option contains the number of excited states  per symmetry. Excitation energies  are calculated for each state and if any operators are given, symmetry-allowed transition moments  are calculated between the reference state and the excited states.

.PRINT  
READ *,IPRINT
Sets print level.

.PROPRT  
READ '(A)', LABEL
Sets A and B to a given operator with label; LABEL. (See section .)

.QUADMO   Sets A and B to the quadrupole  operators.

.RESTPP   Restart  of response calculation. This can only be used if the root which is specified is the same which was used last in the previous response calculation.

.THCPP  
READ *,
Threshold for solving the linear response eigenvalue equation. Default is .

.FREQUENCIES  
READ *, NFREQ
READ *, FREQ(1:NFREQ)
Response equations are evaluated at given frequencies . Two lines following this option must contain 1) The number of frequencies, 2) Frequencies;

.RESTLR   Restart  of response calculation. This can only be used if the operator specified is the same which was used last in the previous response calculation.