Subject: CCL: NDDO semiempirical parameters

From: "Dinbmica" <dinamica^at^webcable.com.br>
Date: Fri, 13 Jun 2003 11:14:08 -0300

Dear CCLers,,

I have a couple of questions about semiempirical parameters in NDDO methods (MNDO, AM1...):

1) Do you have any routine or the iterative formulas to obtain the derived parameters, rho1 and rho2, from the optimized ones (namely 1 center 2 electron integrals, g_ij, and zeta_i) ?? 

2) Can you suggest any references which explicitly comment on the individual influence of the NDDO parameters upon calculated molecular properties?
  E.g.: If one varies the resonance integrals (beta_i), what is the effect upon geometries? Or if one varies the one center one electron integrals (U_ii), what is the effect upon charge distribution?

Thank you very much for your help,

Guilherme Menegon
IQUSP