"Spectrum-only" assignment of core-penetrating and core-nonpenetrating Rydberg states of calcium monofluoride

Abstract

Rydberg states of calcium monofluoride in the n* = 17–20 region have been observed by ionization-detected optical–optical double-resonance spectroscopy via the D2Σ+ v = 1 intermediate state. All members of the six core-penetrating Rydberg series in the n* = 17–20 region and several components of the 17f and 17g core-nonpenetrating Rydberg states have been assigned. While the assignment of core-penetrating Rydberg states is straightforward without use of an effective Hamiltonian model, "spectrum-only" assignment of core-nonpenetrating states is complicated because strong l-uncoupling causes the core-nonpenetrating states to evolve rapidly from Hund's case (b) to Hund's case (d) coupling. We describe "spectrum-only" assignment procedures, developed in the spirit of Gerhard Herzberg, that can be used to assign optical–optical double-resonance spectra of core-penetrating and core-nonpenetrating Rydberg states using only information contained in the spectrum rather than predictions derived from an effective Hamiltonian model. The ambiguities that arise in the assignment of each class of states are discussed in detail.Key words: CaF, electric quadrupole moment, Rydberg states, laser spectroscopy.

A quantum defect model for the s, p, d, and f Rydberg series of CaF

“…CaF has been studied for decades [21][22][23][24][25][26][27][28][29][30][31] and the energies of all of its "s," "p," "d," and "f" Rydberg states, from the ground state of the molecule to the vibrationally excited Rydberg states that lie above the v = 0 ionization limit, are now known to spectroscopic accuracy (to within ∼0.01-0.10 cm −1 ). CaF has been studied for decades [21][22][23][24][25][26][27][28][29][30][31] and the energies of all of its "s," "p," "d," and "f" Rydberg states, from the ground state of the molecule to the vibrationally excited Rydberg states that lie above the v = 0 ionization limit, are now known to spectroscopic accuracy (to within ∼0.01-0.10 cm −1 ).…”

Direct detection of Rydberg–Rydberg millimeter-wave transitions in a buffer gas cooled molecular beam

“…Initial Rydberg states of Ba (n * = 34 -74) and BaF (n * = 35 -50) are located by recording low resolution survey spectra, employing a pulsed field ionization (PFI) TOF-MS detection scheme, described in Ref. [20]. The PFI spectra shown in the difficulty in assigning and interpreting molecular Rydberg spectra due to the combination of a high density of states and limited laser resolution.…”

Polarization dependence of transition intensities in double resonance experiments: Unresolved spin doublets

“…21 Briefly, following the reaction of CHF 3 , seeded in He, with the ablation-formed Ca plasma, the pulsed nozzle creates 350 s long gas pulses at a 20 Hz repetition rate. 21 Briefly, following the reaction of CHF 3 , seeded in He, with the ablation-formed Ca plasma, the pulsed nozzle creates 350 s long gas pulses at a 20 Hz repetition rate.…”