Theoretical atomic physics activities in Bergen.

The theoretical atomic physics group started to work in Bergen with the appointment of prof. J.M. Hansteen in 1967. With his students he started new investigations of the so called SCA model for inner shell ionization. He was joined by gradually several younger scientists, so that during the 1970s the activity of Bergen Atomic Physics Group was very well known internationally, and in this sector of atomic theory was a leading group internationally. Later the studies of inner shell ionization have been extended to various other processes, including electron transfer, interplay of atomic and nuclear processes etc

During the 1980 the interest of the Group gradually shifted to nonperturbative regimes of collisions, i.e. to studies of situations where the presence of two colliding atomic centers can not be viewed as a small disturbance of the stationary states of the colliding partners. In this period a set of computer codes has been developed which are modified and improved to the present day for increasingly complex and more precise studies of atomic collisions.

In 1989 the Group joined a European Network on Geometrical Aspects of atomic collisons (1987-1990) , i.e. collisions where the colliding atoms are prepared by laser field in states with distinct geometrical properties (known also as alignment and orientation). In addition to contributing by the above mentioned codes, the Group also developed methods for graphical analysis and visualization, including animations of electronic wavefunctions during the collisions. (see

The studies of geometrical aspects later called for close examination of the validity of the semiclassical approach, and resulting treatments involving approximate fully quantal approach (also known as eikonal method). In the studies of atomic collisions one is also using a fully classical statistical approach (Classical Trajectory Monte Carlo - CTMC approach). The quantal studies of various processes have also been complemented by such CTMC studies, using computer codes developed by the Group and collaboration partners.

In recent years the research interests of the group are opening towards interactions with photons and with semiclassical strong fields, as provided by strong field lasers. This reflects the general trends in the international community of theoretical atomic physics.

The new development in fundamental quantum theory, in particular the studies of entanglement and quantal interference, were related to various atomic processes. The Group is also engaged in certain such studies.

Classical calculations of many particle systems lead to a method known as molecular dynamics. Studies of fractures and clustering in model systems are also one of the lines of the research followed by the Group and guest researchers and guest students. This line of work is a result of an attempt to pursue a line of basic research which is of direct interest of industrial reseach groups (in this case a long term collaboration project with Norsk Hydro, Karmøy.

One aspect of atomic collision physics is the role of atomic processes in penetration and neutralization of charged particles through the auter atmosphere (Aurora Physics in this case). Several simulation studies are performed and in progress.

At present the staff consists of two permanent researchers, one junior research fellow (stipendiat, PhD student), one professor emeritus, one part time guest researcher (Norsk Hydro), altogether about seven to ten MSc and PhD students financed by various programs, and short time visitors.

International collaboration and networks:

  1. Norfa Network in atomic and optical physics: Coherent Laser-Atom Interactions (1997-1999)
  2. IAEA: Coordinated Research Project (1997-2000): Charge Exchange Data for Fusion Plasma
  3. Representing Norway in General Committee of ICPEAC (International Conference on Photonic, Electronic and Atomic Collisions)

In addition individual collaborative projects with laboratories in Stockholm, Copenhagen, Paris, Prague etc.

In summary, the present main research interests of the Group are:

In general, the main research fields of interest of the Group are very little represented in Norway. In 1995 and 1996 the Group has taken initiative to coordinate all the related research activities in Norway into a larger distributed research group This group would have consisted of only 9 to 10 permanent position scientists, which indicates how little the total activity is. Moreover, no support has been allocated to this project, which shows how little the Norwegian research administrators follow the international development in physics.