Preface to AMPAC™
4.0 Manual

Dear Colleagues,

This version of AMPAC™ represents the beginning of a new era. I have decided to retire at the end of this year, and Professor Andrew Holder, a former member of my research group, now at the University of Missouri - Kansas City, has agreed to take over the AMPAC project and also the development and promotion of new theoretical procedures. Several other former members of my group have already agreed to assist Andy in the development and support of AMPAC .

One other change concerns the distribution of AMPAC. Andy Holder is intending, at my suggestion and with my full approval, to publish AMPAC 4.0 and any future programs on a commercial basis. There are three good reasons for this change:

FIRST, to prevent proliferation for the sake of proliferation. My only concern is that other programs should not cause confusion by calling themselves versions of AMPAC. Fortunately, I possess legal rights to the term “AMPAC,” which I have, of course, passed to Andy.

SECOND, to provide secure funding for the further development of semiempirical methods.

THIRD, because it seems only fair that the chemical industry should contribute to a project which has proved of great value to them and is likely to be of even more value in the future.

Since this will be the last version of the AMPAC program with which I am directly associated, I would like to make three closing comments:

The term “quantum chemistry” should imply the area of science concerned directly with the use of quantum theory as an aid in solving chemical problems, and work in this area should be judged solely by its value to chemistry.
The basic idea behind the semiempirical approach is that the practical effectiveness of any procedure can be upgraded to an incredible extent by introducing parameters whose values are adjusted to fit experiment. If one is concerned with results, this is the way to get them at minimum cost.
AM1 is by no means the end of the road concerning “semiempirical” SCF MO treatments. On the contrary, the conventional semiempirical approach seems likely to remain for many years the best practical way to use quantum theory as a chemical tool. Far better procedures are being developed, and in fact we have pioneered a “fourth generation” successor to AM1, the Semiempirical ab initio Method, Version 1 (SAM1).

Andy has my best wishes for success, and I know that he will carry on the development and expansion of the semiempirical methods that I invented and have for so many years promoted.

Yours sincerely,

Michael J. S. Dewar

August 1, 1992


Conventions Used in This Manual		Preface to AMPAC™ 5.0 Manual

Preface to AMPAC™ 4.0 Manual

Preface to AMPAC™
4.0 Manual