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19.9.1 Gradients for SA-MCSCF

For computing state-averaged gradients, use

CPMCSCF,GRAD,state,[SPIN=spin],[MS2=ms2],[ACCU=thresh],[RECORD=record]

where state specifies the state (e.g., 2.1 for the second state in symmetry 1) for which the gradients will computed. spin specifies the spin of the state: this is half the value used in the corresponding WF card (e.g., 0=Singlet, 0.5=Doublet, 1=Triplet). Alternatively, MS2 can be used, where ms2 = 2*spin, i.e., the same as specified on WF cards. The specification of SPIN or MS2 is only necessary if states with different spin are state-averaged. record specifies a record on which the gradient information is stored (the default is 5101.1). thresh is a threshold for the accuracy of the CP-MCSCF solution. The default is 1.d-7.

The gradients are computed by a subsequent call to FORCES or OPTG.

Note: if for some reason the gradients are to be computed numerically from finite energy differences, it is in state-averaged calculations necessary to give, instead of the CPMCSCF input, the following:

SAVE,GRAD=-1

Otherwise the program will stop with an error message.



Next: 19.9.2 Difference gradients for Up: 19.9 Coupled-perturbed MCSCF Previous: 19.9 Coupled-perturbed MCSCF   Contents   Index   PDF

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