https://doi.org/10.1140/epjd/e2003-00200-0
Effects of electric fields and collisions on highly excited rubidium atoms
Departments of Chemistry and Physics, The University of Tennessee, Knoxville
TN 37996, USA
Corresponding author: a rcompton@utk.edu
Received:
12
November
2002
Revised:
11
March
2003
Published online:
8
July
2003
The effects of static and pulsed electric fields on the multiphoton ionization (MPI) of rubidium atoms at both low (atomic beam) and high (heat pipe) densities are studied using tunable OPO lasers. Two-photon excitation of np states is induced by the external electric field at both low and high densities. In addition, np signal is also seen at very low electric fields in the heat pipe, providing evidence for collision mixing as well as field mixing. At low Rb densities strong resonance features are observed in the energy region between the zero field limit (IP) and the field ionization limit. In addition, collisional detachment and charge transfer between excited ns and nd Rb Rydberg states and nozzle-jet cooled polar molecules (acetonitrile and acetone) are studied under crossed-beam conditions. The formation of dipole bound anions for acetone is only seen under nozzle jet expansion conditions and the maximum in the Rydberg electron transfer (RET) rate versus n depends upon the expansion gas (nmax increases in the order H2, He, Ne, Ar, Xe). For acetone (low dipole moment and large nmax), collisional detachment dominates the charge transfer, whereas for acetonitrile (high dipole moment and low nmax), charge transfer is seen to dominate the creation of Rb+.
PACS: 33.80.Rv – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) / 34.60.+z – Scattering in highly excited states (e.g., Rydberg states) / 34.70.+e – Charge transfer
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003