C15. Commission on Atomic, Molecular, and Optical Physics

Report to the IUPAP Council and Commission Chair Meeting
Mexico
September 28-29, 2001

Conference - ICPEAC XXII

The twenty second meeting of the International Conference on Photonic, Electronic and Atomic Collisions was held July 18-24, 2001 in Santa Fe, New Mexico, USA. Approximately 650 scientists attended from about 40 different countries. This conference was supported by IUPAP.

The ICPEAC conferences are chartered to foster the growth and exchange of scientific knowledge in the field of photonic, electronic, and atomic collisions as well as related areas of atomic, molecular, and optical physics. In general, these conferences cover few-body interactions between photons, electrons, positrons, ions, atoms, molecules, and clusters.

Future ICPEAC meetings include

2003 Stockholm (Sweden) July 23-29
2005 Buenos Aires (Argentina) July 14-19
2007 Heidelberg (Germany) July 25-31

Some Recent Results

Unified theories, applied to cosmology, allow space and time dependence of the coupling constants. Spectroscopy of gas clouds which intersect the sight lines to distant quasars provide stringent constraints on variation of the fine structure constant a. A comparison of such data with new high precision laboratory measurements of optical spectra yields a smaller a in the past, see J.K. Webb et al., Phys. Rev. Lett. 87 (2001) 091301-1.

Recent progress in experimental studies of Bose-Einstein Condensates (BEC) includes a way to make a BEC in an optical trap (instead of magnetic trap) before the evaporative cooling process. Such a trap opens the possibility of forming condensates of non-magnetic atoms, of several spin states of the same atom and of molecules. (M.D. Barrett et al., Phys. Rev. Lett. 87 (2001) 010404-1.

The molecular ion H3+ plays a key role in interstellar chemistry and star formation. Many experimental and theoretical studies have been carried out of the rate of destruction of H3+ by electrons (dissociative recombination) but the results are quite contradictory and no theoretical treatment has been in agreement with the best experimental data. However, by identifying a previously neglected decay mechanism, a very recent theoretical calculation (V. Kokoouline et al., Nature 412 (2001) 891) has bridged the gap between theory and experiment.

C15 Activity

The C15 meetings take place during the biannual ICAP conferences, and the next meeting will be held at the end of July 2002 at MIT. In 2001 the contacts have taken place by electronic mail, e.g. concerning conference support. A discussion has also been started about closer contacts between C15 and atomic/molecular/optical divisions such as DAMOP in North America and the Atomic and Molecular Physics Division of the EPS. Extended contacts with Eastern Europe have also been discussed. In this context Latvia was encouraged to apply for membership in IUPAP. Atomic and molecular physics, together with solid state physics, belong to the dominant physics activities in Latvia.

Indrek Martinson
Chair C15