Seminar Reminder

Date: Thu, 22 Apr 93 09:36:58 -0500
From: cobb
Message-id: <>
To: mcs
Subject: Seminar Reminder

                        Argonne National Laboratory
                  Mathematics and Computer Science Division

         New Methods for Ab Initio Calculations on Very Large Systems

                                 Jan Almlof
                           University of Minnesota
                               Minneapolis, MN

                      10:30AM, Thursday, April 22, 1993
                     Building 221, Conference Room A216


The talk will present several unconventional approaches that can be  
used to avoid bottlenecks which are usually encountered in ab initio  
quantum chemistry.

I will give a brief overview of the latest development in direct  
techniques. These methods were introduced in Hartree-Fock  
calculations some time ago, and are now being refined and extended to  
encompass correlated electronic structure methods.  By avoiding the  
storage of integrals, it is obvious that disk size limitations are  
completely circumvented.  Less obvious but equally important is the  
fact that in the direct scheme one can avoid the calculation and  
processing of four-center, two-electron integrals altogether.   
Techniques to exploit this feature will also be discussed in the  

As the systems under study become larger, it is possible to introduce  
very important simplifications due to their `semi-classical'  
behaviour in the macroscopic limit, using techniques and concepts  
familiar from density functional theory.  I will discuss such  
techniques, and try to predict how they will affect computational  
chemistry in the future.  Finally, I will also describe how the  
development and application of these methods are being influenced by  
recent progress in computer hardware, especially by the emerging  
parallel computing technology.


Coffee and Donuts will be served in the interaction room prior to the