Subject: LCAOSCF : how to get self-consistency ?

From: Leonardo Demaria <[email-masked]>
Date: Wed, 14 Aug 1996 14:14:21 +22310718 (MET_DST)

Hi everybody, I'm doing some CNDO/2 calculations for solid carbon and
fullerenes. I've found some problems with the convergence of the itera-
tive solutions of the Roothaan equations. There are some cases in wich
the density matrix doesn't converge but oscillates and finally diverges.
Is there any body out there who can tell me about some technical referen-
ces about how to deal with the convergence of such equations?
I've been using only the previous step density matrix in order to compute
the next one but I know that relaxation techniques can be used. 
Can somebody tell about relaxation techniques in the solution of the
SCFLCAO equations?
I thank you very much in advance and I hope somebody is still at work
somewhere. Bye,
-- 
                        Leonardo De Maria                  
          SISSA                  |      Universita di Trieste 
    Scuola Internazionale        |   Dipartimento di Fisica Teorica 
  Superiore di Studi Avanzati    |       Strada Costiera 11
   via Beirut 2-4, Grignano      |       Miramare-Grignano
      I-34014 - Trieste          |       I-34014 - Trieste
   tel:    +39 40 3787506        |   tel:     +39 40 224265
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