Table of contents

Different schemes for the formation of cold molecules via photoassociation are discussed. In a typical magneto-optical trap, the formation rates can reach 0.2 cold molecules per second and per atom. The measured temperatures of the cold molecular samples are in the range 10–200 µK. The possibility for accumulating the so-formed cold molecules inside a trap, or for selecting them in a well-defined level in ground state are analyzed.

Experiments aimed at laser cooling and trapping of radioactive atoms are nowadays operational at several laboratories. They open up a bridge between atomic and nuclear physics, allowing new precise spectroscopic measurements and detailed analysis of nuclear decay processes. A magneto-optical trap (MOT) for francium atoms is almost operational at the INFN Legnaro laboratories; its characterization and optimization are under way. Measurements of francium production rate as a function of target temperature, primary beam intensity and energy have been carried out. Preliminary tests with other stable alkali atoms, aimed at an improvement of the MOT collection efficiency, are reported.

We present an intense source of ⁸⁷Rb atoms that has been set up to produce a continuous, slow and cold beam in a magnetic guide. It consists of a two-dimensional magneto-optical trap whose cooling laser power is provided by a master-oscillator tapered-amplifier system. This trap produces an atomic beam with a flux of over 10¹⁰ atoms/s and a mean velocity of 40 m/s. The beam is recaptured by a second trap whose purpose consists in reducing the beam's velocity, in further cooling the atoms and injecting them into the magnetic guide. The article focusses on the first stage of the process described above.

We review our work towards attosecond pulse train metrology. The attosecond pulses result from coherent superpositions of odd harmonics of the Ti : Sapphire laser, produced in atomic gases used as non-linear medium.

Optically pumped magnetometres (OPM) are known as the most precise instruments for scalar measurement of low magnetic fields, including those of the Earth's magnetic field. For a long time OPM could not compete, in absolute accuracy, with the proton precession magnetometers, being, at the same time, much more sensitive and fast. Nowadays, due to the considerable progress in the OPM performance, several types of OPM became much more accurate than the best proton magnetometer. During the last decade the main progress was associated with OPM of the following three types: (1) The narrow-line potassium M_x-OMP with the highest shot-noise-limited resolution (about 10 fT/Hz^1/2) and with an absolute accuracy better than 0.1 nT; (2) The "tandem" M_x–M_z-type magnetometer with a narrow line potassium M_z unit of enhanced absolute accuracy (of about 10 pT); (3) The laser pumped ³He free-precession magnetometer of highest absolute accuracy and lowest energy consumption. Each of these three types has its own specific features, preferable in certain applications.

We review principally some recent work carried out in Belfast and Heraklion which handles the few-electron dynamics of atomic and molecular systems exposed to high frequency, high intensity laser fields. The design and application of the quantitatively accurate computational methods is discussed. The Belfast work is illustrated by results for double ionization of helium and the hydrogen molecule where in each case the two electrons have been handled in full-dimensionality. The first results for multiphoton, double ionization of a complex atom, namely magnesium demonstrate an important application of the Heraklion approach.

We present an overview of the recent developments concerning the spectroscopic properties of lanthanide atoms and ions (Z = 57–71). This review is focussed on the advances made during the past twenty years regarding the analysis of the spectra, the transition probabilities, the radiative lifetimes and also the hyperfine structures and isotope shifts. Theoretical aspects as well as experimental measurements are both covered in this paper including bibliographical references up to the end of 2001. Some astrophysical implications of the new atomic data concerning the chemical composition of the sun are briefly reviewed. Emphasis is also put on the new database D.R.E.A.M. developed on a web site of Mons University in Belgium.

A computer program for managing extended spectral line lists is presented, which allows classification of previously unknown lines via their expected hyperfine patterns. The program also includes several search strategies for finding unknown energy levels from unclassified lines. Some examples for the Ta I and the Ta II spectra are given, and the discovery of 11 Ta I levels of odd parity and 3 Ta II levels of even parity is reported. These latter levels are the highest known Ta II energy levels.

Fourier transform spectroscopy has proven to be a useful tool when measuring wavelengths and branching fractions. The high spectral resolution makes it possible to extend and improve term analyses of complex spectra. We present an overview of our measurements with the Fourier transform spectrometer at Lund Observatory. Much of our work is motivated by astrophysical problems, and we show an application of some of our measurements related to the age determination of the Galaxy.

Developments in vacuum technology as well as in ion trapping techniques has opened for new possibilities for experimental studies of long-lived metastable states. Since long it has been realized that such levels are of great importance for both fundamental theory and many different kinds of applications. Before the advent of modern technology it was, however, practically impossible to study forbidden transitions from metastable levels in the laboratory. In this review article some of the new experimental methods are briefly described. In particular, the laser probing technique for a stored ion beam developed at CRYRING is described. Recent results for singly charged ions with extremely complex structure are presented. Systematic effects are discussed.

We report several spectroscopic investigations of atomic and molecular species based on semiconductor diode lasers. We first discuss the isotope shifts and hyperfine structures of several near-infrared transitions of Ar and Xe. Peculiar isotope displacements observed for these atoms were ascribed to their closed nuclear shells configuration (magic nuclei).

Diode lasers were also used to generate narrow-bandwidth tunable radiation around 3 µm by means of difference-frequency generation in periodically-poled lithium niobate crystals. Mid-IR radiation was used either to investigate collisional broadening of water vapor lines in the ν₁ band and to perform an high sensitivity detection of the N₂O molecule.

The NIST Atomic Spectra Database is reviewed, and the additions planned for the near-term and longer range future are discussed. Two examples are presented, illustrating the often still unsatisfactory state of transition probability data, which shows the need for updates of the database when significant amounts of improved data become available.

Saturation in the laser output power at high electrical currents is experimentally observed for a He–Cu⁺ IR HCD laser. To investigate which mechanisms might be responsible for the laser power saturation, a modeling network is developed for a helium-argon-copper hollow cathode discharge (HCD), and is applied to the conditions for which saturation is observed. Typical calculation results, such as the potential distribution, the densities of the various plasma species, the sputtering flux and the ionization degree of copper, are presented as a function of electrical current. The calculated densities of electrons, Cu atoms and Cu+ ions, as well as the sputtering flux and the ionization degree of copper, increase with electrical current, whereas the He⁺ ion density is found to be constant. The laser output power itself cannot yet be predicted by the model, due to insufficient knowledge about the relevant populating and depopulating processes of the upper and lower laser levels and the corresponding cross sections. However, the model can make predictions on the production of the upper laser level (by asymmetric charge transfer between Cu atoms and He⁺ ions). The latter is found to increase less rapidly with current at higher values of the electrical current, which is attributed to the rise in gas temperature at higher electrical currents, and it suggests a certain degree of saturation in the laser output power. However, full saturation in the production rate of the upper laser level was not obtained with our calculations. Hence, the observed laser power saturation at high currents is probably also due to (i) either increasing depopulation of the upper laser level, or (ii) increasing population of the lower laser level, resulting in a drop in the population inversion.

High pressure pulsed discharge with cesium vapor could become a very promising lamp, because of its white light properties. It has considerable losses in the infrared spectral region and negligible contribution in the near UV spectral region. We shall present the results of extensive spectral studies of such a lamp with a special emphasis on the near infrared and near UV portions of emission spectra for a variety of experimental conditions. We shall discuss the origin of atomic emission lines and some peculiar molecular bands, which contribute to the overall emission in these spectral regions.

These proceedings include the invited papers of the 34th Conference of the European Group of Atomic Spectroscopy (EGAS34) and selected progress reports.

The 34th EGAS was organized by the Institute of Solid State Physics, Bulgarian Academy of Sciences and the Faculty of Physics, Sofia University. It took place from 9 to 12 July 2002 in Sofia, Bulgaria. 169 scientists from 31 countries participated in the conference.

During the conference 'hot', unpublished results were presented. The modern topics of the atomic spectroscopy—quantum optics, complex atom structure and properties, laser spectroscopy and applications of atomic spectroscopy in astrophysics, plasma physics, were the subjects of 14 invited lectures, 4 progress reports, 37 oral contributions and 136 poster presentations.

The participants could benefit not only from the high scientific level of the conference program but also from a social program in the surroundings of Sofia.

One of the main goals of the EGAS conferences is to give opportunities to young scientists to present their results and to have discussions with leading scientists.

The EGAS34 was supported by EC in the framework of the High-Level Scientific Conferences Program (contract HPCF-CT-2001-00338). Under the contract 60 young scientists from EU and associate countries had the opportunity to participate in the conference. The European Physical Society supported the participation of young scientists from Russia, Croatia and Poland.

The organizers are grateful to all sponsors and organizations for their support.