Page 16 - Strategies and Applications in Quantum Chemistry From Molecular Astrophysics to Molecular Engineer

Quantum Chemistry: The New Frontiers

J. TOMASI
Dipartimento di Chimica e Chimica Industriale. Università di Pisa
Via Risorgimento 35, 56126 Pisa, Italy

1. Introduction
The members of the scientific community are accustomed to work within a frame of rules,
laws protocols, which constitutes the accepted paradigm of a specific discipline. Moreover,
the paradigms of the various disciplines, or the scientific programs, if one prefer a different
terminology [1], are interrelated and connected in a wide and at the same time tight set of
general truths and criteria which constitutes the basic layout of science. Innovation means
to modify protocols, to question truths, to introduce new models and ultimately to infringe
rules, if necessary, but all these innovations are accurately examined before presentation to
the community, planned and justified according to considerations inherent to the specific
protocol and of the general layout of correct scientific methodology.
Things are different when a scientist has to give a overview of the future trends of his
discipline. Prediction is an art, more than a science, and also the more modest goal of a
critical appraisal of the trends of evolution, and of selection of a set of themes for which
progress is expected or hoped cannot be performed with the same instruments used in the
everyday research.
I will thus rely on my tastes, my biases, with an attempt of tempering them with
considerations on the past.

This modest essay will be inserted in a book in honour of Gaston Berthier. He is decidedly
more qualified than myself to undertake this task, having a far larger experience and clearer
ideas on what is good or less good in the theoretical chemistry production. It is a detriment
for the book that Berthier is not the author of these pages. The collection of authors
gathered here to honour Berthier, and the titles of the contributions they are providing for
the book lead me to suspect, and to hope, that the reader will derive a clearer and better
idea of the future trends in quantum chemistry by the global appreciation of the whole book
rather than by the lecture of these few pages.

2. The "modern" quantum chemistry of the past 30 years
Theoretical chemistry may be considered an old discipline: the first steps of "modern"
chemistry (in the 18th century!) are imbued of theoretical considerations, and in the course
of the past century theoretical arguments and approaches have grown into a wide body of
methods and concepts which can be collected under the heading "Theoretical Chemistry".
In the last decades there has been a remarkable shift, making more precise and restricted
1
Y. Ellinger and M. Defranceschi (eds.), Strategies and Applications in Quantum Chemistry, 1–17.
© 1996 Kluwer Academic Publishers. Printed in the Netherlands.