Triatomic Hydrogen
Welcome to the Triatomic Hydrogen Group at the Department of Molecular and Optical Physics - University of Freiburg, Germany

Electric-field ionization of Rydberg states of H3
C. Bordas1 and H. Helm2
1Molecular Physics Laboratory, SRI International, 333 Ravenswood Avenue, Menlo Park, California 94025
2Department of Molecular and Optical Physics, Albert-Ludwigs-Universität, Hermann-Herder-Strasse 3, D-79104  Freiburg, Germany


The stability of Rydberg states of triatomic hydrogen in an external electric field is investigated for principal quantum numbers ranging from n=50 to 110. When excited in the presence of an electric field, the states with an electric-field projection of the total angular momentum MN=0 are found to be rapidly field ionized above the classical saddle-point energy. However, a significant proportion of the states for MN=1 is observed to be stable above this threshold, with lifetimes exceeding 10-6 s. A perturbative treatment of the molecular Stark effect indicates that different behavior of MN=0 and 1 Stark states is a consequence of the stronger coupling among the states of the MN=0 manifold. Following excitation under near-zero field conditions, a predominantly diabatic evolution of the Stark manifold of H3 is observed, for slew rates of a few times 107 (V/cm)/s. This behavior results from the nondefinition of the projection of the total angular momentum of the molecule excited at near-zero field, where a broad manifold of l states is prepared within the bandwidth of the laser. For a comparison, similar experiments are carried out in atomic hydrogen and helium. ©1993 The American Physical Society

©1993 Phys. Rev. A 47, 1209-1219 (1993)

DOI: 10.1103/PhysRevA.47.1209
PACS: 33.90.+h, 32.60.+i

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