David R. Cok

Hyperfine and spin–rotational structure of CaBr X 2Σ (v = 0) by molecular‐beam laser‐rf double resonance

The molecular‐beam, laser–rf, double‐resonance technique has been used to make high‐precision measurements of the spin–rotation and hyperfine interactions in the X 2Σ (v = 0) electronic ground state of Ca79Br and Ca81Br. The spin–rotation interaction is found to have a strong N dependence. The Frosch–Foley magnetic hyperfine parameters b and c and the electric–quadrupole hfs parameter eqQ are determined for both molecules.

Hyperfine structure of the X 2Σ+ ground state of Ca 35Cl and Ca 37Cl by molecular‐beam, laser‐rf double resonance

The hyperfine structure of the X 2Σ+ state of Ca 35Cl and Ca 37Cl, unresolved in previous studies, has been investigated in detail by the molecular‐beam, laser‐rf, double‐resonance technique. Results for the spin‐rotation interaction and the dipole and quadrupole hfs constants are given in the form of Dunham coefficients so that the N\ and v\ dependence of each constant can be explicitly exhibited. The results, after dividing out the purely nuclear effects, fall between the corresponding values for CaF and CaBr, as expected.

New line classifications in Ho i based on high-precision hyperfine-structure measurement of low levels

Doppler-free laser-fluorescence and laser-rf double-resonance studies have been made of the hyperfine structure (hfs) of four strong, previously unclassified visible lines in Ho i; all are shown to connect with low levels. The hfs of the 4f116s24I11/2,9/2 levels is measured in detail, allowing evaluation of the dipole (a01, a12, a10) and quadrupole (b02, b11, b13) hfs radial integrals. The results are in close agreement with the ab initio values of Lindgren Rosen [ Case Stud. Atom. Phys.4, 93– 292 ( 1974)]. The value found for b02 in the 4f116s2 configuration is in reasonable agreement with that of Wyart Camus [ Physica93C, 227– 236 ( 1978)], thereby confirming their finding of a substantial dependence of this parameter on the number of 4f electrons in the core.

Hyperfine structure of the A 2 Π state of Ca 35 Cl

The hyperfine structure (hfs) of the A2Π excited state of Ca35Cl has been investigated by using the new rf-pumped, laser-rf double-resonance technique. The optically unresolved hfs components of the R2 (N″ = 101), A ↔ X (0,0) line were resolved by double resonance, and the measured splittings, when combined with the known X2∑+- state hfs spacings, show that the A2Π-state hfs splittings are not more than 1 MHz.

Vibrational, rotational, and isotopic dependence of CaBr X2Σ spin-rotational and HFS parameters

Abstract The previously published molecular-beam, laser-rf, double-resonance study of the rotational and isotopic dependences of the spin-rotational and hyperfine interactions in the v ″ = 0, X 2 Σ state of CaBr is supplemented here with data for v ″ = 1. The vibrational dependence of the parameters is now obtained. The results for CaBr are displayed along with analogous, previously published results for CaF and CaCl.

Molecular-Beam, Laser-RF, Double Resonance Studies of Calcium Monohalide Radicals

The molecular-beam, laser-rf, double-resonance technique has been described [1–3] a number of times. In essence, the occurrence of a radiofrequency (rf) transition in the electronic ground state of the molecule under study is detected by an increase in the laser-induced fluorescence of the molecular beam when the rf is on resonance. The technique makes it possible to measure small energy splittings (normally spin-rotational or hyperfine) in the electronic ground state of a molecule to an absolute precision of 1 kHz. The sensitivity of the technique is high because even a very small increase in fluorescence can be easily seen if the rf is swept repeatedly and digital data-handling techniques are used. The technique is useful for ionic [4] as well as for neutral atoms and molecules.