1996 Report in Acta Cryst, May 9, 1997
Commission on Charge, Spin and Momentum Densities

The Commission continued to promote the study of electron density distributions in both real and momentum space by bringing together physicists, chemists and crystallographers in conferences, workshops and schools and by initiating and carrying out projects.

It was decided to set up a World Wide Web page (http://www.tuwien.ac.at/theochem/iucr/csmd.html) linked to the IUCR www-page with continuously updated information. This page contains the members of the Commission, their addresses (including e-mail) and their main activities. Reports and projects will be announced there.

With great sorrow, we learned of the passing away of our member T.Maslen in February 1997.

Meetings of the Commission

The Commission met during the XVII Congress and General Assembly of the IUCr in Seattle (August 1996). The following topics were discussed: the next Sagamore and Gordon conference (see below) and the progress of the projects (see below).


First European Charge Density Meeting. The meeting was organized by Claude Lecomte and was held at the "Abbaye des Prémontrés" (14-16 November 1996). Session included material sciences, maximum entropy, high-resolution synchrotron data, electrostatics, modeling of charge density and transferability, extension of experimental work to large systems and their theoretical calculations. This meeting starts a new series to be held every three years.

Sagamore XII conference. This conference will be held in Saskatchewan, Canada, 27 July – 1 August 1997, and is organized by B.Robertson. The main areas will be electrostatic potentials, magnetization, positron annihilation and Compton scattering and thus the conference has a stronger emphasis on solids and physics.

Gordon Research Conference. The next Gordon conference on "Electron Densities and Chemical Bonding" will take place for the first time in Europe, namely at Queen’s College in Oxford, UK, 30 August – 4 September, 1998. K.Schwarz and C.Lecomte were selected as Chairman and Vice-Chairmen. In this conference chemistry and molecules play an important role, although the interdisciplinary nature of this topic will be stressed.


The Commission carries out presently five projects (the person in charge is given in parenthesis). Additional information can be found on the corresponding www-page with continuously updated information.

1. Density Matrix (Wolf Weyrich). A progress report is expected at the Sagamore meeting.

2. Fermiology (Arun Basil). This is on of the main topics at the next Sagamore meeting.

3. Maximum Entropy (Makoto Sakata). This topic has led to vigorous scientific discussions during various conferences. Therefore independent activities are highly encouraged and should help to clarify the pros and cons for future applications.

4. Multipole Refinement (Claude Lecomte). For an inorganic candidate it was generally agreed that Al2O3 (corundum) was the most suitable test case. A first report on corundum is planned for Sagamore XII, where suitable controsymmetric organic systems should be discussed.