Subject: analytical gradient

From: [email-masked] (Antonio Buljan)
Date: Thu, 27 Mar 1997 14:36:10 -0800 (PST)

Hello!  

I'm interested in the applicability of semiempirical quantum
methods in the study of solids. First of all, I'd like to minimize
energy, so I'm looking for the formula of the analytical gradient of
extended-Huckel-energy for solids. That's to say, the analytical
derivatives of this energy. In 1981 Beran et al. developed a expresion
for this derivative for the molecular and a non-geometry-dependent
Wolfsberg-Helmholtz parameter K. Does anybody know which is or where
can I find the expression for the derivative of the energy in a band-
calculation of solids with the distance-dependent K used in the ASED
method?

Antonio Buljan

-- 
***********************************************************************
ANTONIO BULJAN HERNANDEZ

Despatx 422                             
Departament de Quimica Fisica             
Facultat de Quimica                          
Universitat de Barcelona                      
Marti i Franques, 1
08028 Barcelona, CATALUNYA (Espanya)                     
                                                
telefono-1: 34-3-402 90 21   
telefono-2: 34-3-402 12 70                        
fax       : 34-3-402 12 31                          
e-mail: [email-masked]            
web-site: http://linus.qui.ub.es/~antonio 
**********************************************************************