The Predissociation Mechanism for 2Sigma+ Rydberg States of CaCl

Kinetic and dynamic aspects of lifetime oscillations in the predissociation of hydrogen chloride ions

The predissociation dynamics of hydrogen chloride ions (HCl+ and DCl+) in the electronic A 2Sigma+ state has been investigated by solving the time dependent Schrödinger equation. The predissociation lifetime is shown to strongly depend on the vibrational and the rotational quantum number, with quasi-periodic oscillations. Rovibronic states, which exhibit lifetimes about 1 order of magnitude larger than those of neighboring states, are termed rotational islands of stability (RIS). These RIS can be correlated with characteristic reference energies, e.g., the difference between rovibronic eigenenergy and the energy of crossing of rotronic bound and repulsive potentials. The origin of these RIS is illustrated by model studies of the positions of the nuclear wave functions involved.

Core-Penetrating Rydberg Series of BaF: Single-State and Two-State Fits of New Electronic States in the 4.4 </= n* </= 14.3 Region

We report results of optical-optical double-resonance studies of the Rydberg states of the BaF molecule in the energy region of E = 33 100-38 200 cm(-1) (4.4 </= n* </= 14.3). Barium monofluoride molecules have been produced in a resistively heated high-temperature oven from BaF(2) powder mixed with a small amount of boron powder. We have observed more than 50 new electronic states. Forty-nine of them have been rotationally analyzed and assigned to eight Rydberg series (four (2)Sigma(+), one (2)Pi, two (2)Delta, and one (2)Phi). Single-state and two-state fits have been carried out. Multiple local perturbations have been analyzed. Formation of supercomplexes in the Rydberg spectrum of BaF has been discussed. Copyright 2001 Academic Press.

Double-Resonance Spectroscopic Studies of Core-Penetrating Rydberg States of CaCl

Six core-penetrating Rydberg series have been assigned in the CaCl molecule by a combination of double-resonance spectroscopic techniques. Two 2Sigma+ series, with approximate quantum defects (delta) of 0.51 and 0.25, have been observed with effective principal quantum numbers (n*) in the range of 5-8 using the D2Sigma+ state as the resonant intermediate state for REMPI and/or ion-dip detection. A third 2Sigma+ series with delta approximately 0.84 and a 2Delta series with delta approximately 0.95 have been observed with n* = 16-18 using the A2Pi3/2 state as the resonant intermediate state for preparation of v+ = 1 vibrationally autoionizing states. Two additional series in the same region with delta approximately 0.90 and 0.07 are tentatively identified as the expected core-penetrating 2Pi series. Vibrational assignments have been confirmed in many cases on the basis of isotope shifts between the 35Cl and 37Cl isotopomers. The ion-dip and REMPI spectra display linewidths systematically broadened by predissociation. In addition to the assigned core-penetrating series, both the REMPI and the ion-dip spectra display some sharper features that have not yet been assigned. These sharper features most likely arise from perturbations of optically "bright" core-penetrating states by nominally "dark" higher-l core-nonpenetrating states. Copyright 1999 Academic Press.