O. Hoffmann

Accurate probing of the repulsive X2Σ and B2Σ potentials of NaNe and NaAr by differential optical collision experiments

The oscillations observed in the differential cross section of the optical collisions Na(3s)+M+hν→ Na(3p)+M with M = Ne, Ar are compared with theoretical results from coupled-channels calculations using the best available potentials. Generally, a very good agreement is found. We conclude that repulsive interatomic potentials can be probed by this method with an accuracy of the order of only a few cm-1.

Oscillatory differential cross sections for Li+He, Ne, H2, and D2 optical collisions

We report measurements of differential cross sections for optical collisions of Li atoms with He and Ne atoms and H2 and D2 molecules. Oscillatory structures are observed in all cases. For the atomic targets, we find a very good agreement with theoretical results based on close-coupling scattering calculations and recent quantum chemical data, and we derive estimates for the accuracy of the calculated potentials. For the molecular targets, calculations using the rotational sudden approach yield a good agreement with the experiment.

Simultaneous optical excitation of Na electronic and CF4 vibrational modes in Na+CF4 collisions

We report on the ultraviolet excitation of Na(3s)+CF(4) collision pairs in a crossed molecular beam experiment. We observe Na(3d) collision products originating from the process Na(3s)+CF(4)(nu(3)=0)+hnu-->Na(3d)+CF(4)(nu(3)=1). The spectral intensity distribution of the collision products and the prevailing small angle scattering confirm a previously proposed long range dipole-dipole mechanism. We report velocity-resolved spectra and a comparison to preliminary numerical results based on collisional broadening theory. Polarization experiments suggest future potential for the observation of collision geometries.

The X2Ʃ+, A2π and B2Ʃ+ potentials of NaNe from a combined analysis of optical collision and spectroscopic data

We present new measurements of differential cross sections for the optical collision process for an extended range of optical detunings. A combined analysis of the present scattering results and the earlier NaNe laser-spectroscopic data by Lapatovich et al (1980 J. Chem. Phys. 73 5419) for optical transitions A-X and B-X is performed using a coupled channels approach in both cases. We obtain the Born?Oppenheimer potentials for the ground state and the excited states and as well as the diagonal and off-diagonal spin-orbit functions of the NaNe van der Waals molecule for a wide range of atomic distances.