[molpro-user] Problem with maxit in FCI

John S. Sears john.sears at chemistry.gatech.edu
Thu May 22 03:46:20 BST 2008

Dear users
I am having a problem with some FCI computations in molpro 2006.1. The FCI
calculation is not quite converged in 35 iterations. I set the maxit keyword to
50 in the fci card and the program appears to recognize it. The output even
prints the maximum number of iterations

 Run Hamiltonian processor DAVIDSON
 Symmetry:                   2
 Trial vector:                  0.00
 Result vector:                 0.00
 Maximum iterations:           50
 Convergence threshold:         0.0000100
 RHS vector:                    0.00
 Hamiltonian shift:             0.0000000
 Output threshold:              0.0500000
 Options:                        0

However, at the end of the 35th iteration the program stops

 35   125044.6  0.00263340   -56.67373865
+                                         0.06 -0.00000219 -0.00000210
0*** Convergence not achieved in max iterations

Any advice here would be greatly appreciated.

John S. Sears
Postdoctoral Research Associate
Center for Computational Molecular Science and Technology
Center for Organic Photonics and Electronics
School of Chemistry and Biochemistry
Georgia Institute of Technology
Atlanta, GA 30332-0400

More information about the Molpro-user mailing list