UNIVERSAL AND NONUNIVERSAL STATISTICAL PROPERTIES OF LEVELS AND INTENSITIES FOR CHAOTIC RYDBERG MOLECULES

We study Rydberg molecules taking into account the interaction between the rotational motion of the nuclei and the radial motion of the elec tron. This situation can be treated to a good approximation in quantum mechanics by the multichannel quantum-defect method which in turn has a well-defined classical limit. We are able to calculate very long se quences of levels and the corresponding amplitudes of wave packets. Th is allows us to study the statistical properties of both in detail. Ou r interest focuses on aspects of ''quantum chaos'' that can be particu larly well understood in this case. Our main result is that, in a comp letely chaotic classical situation, where statistics of quantum-level spacings follow the expected universal Gaussian-orthogonal-ensemble be havior, and statistics of line intensities display the expected univer sal Porter-Thomas behavior, nonuniversal properties are explicitly con tained in correlations between intensities and spacings, determined by the time needed for the classical system to mix on a length scale giv en by the quantum wavelength.