Rotation dependence of electric quadrupole hyperfine interaction in the ground state of molecular iodine by high-resolution laser spectroscopy

Abstract

Doppler-free high-resolution spectroscopy is applied to molecular iodine at 532 nm by Nd:YAG lasers. The main hyperfine components as well as the crossover lines are measured for R(56)32-0 and P(54)32-0 transitions by heterodyne beating of two I 2-stabilized lasers. The measured hyperfine splittings including both main and crossover lines are fitted to a four-term Hamiltonian, which includes the electric quadrupole, spinrotation, tensor spin-spin, and scalar spin-spin interactions, with an average deviation of ϳ1 kHz. Absolute values of the electric quadrupole hyperfine constants for both the upper and the lower states are obtained. The rotation dependence of the ground-state (vЉ ϭ 0) electric quadrupole constant eQqЉ is found to be eQqЉ(J) ϭ Ϫ2452.556(2) Ϫ 0.000164(5)J(J ϩ 1) Ϫ 0.000000005(2)J 2 (J ϩ 1) 2 MHz.

Saturated absorption and crossover resonances in a high-finesse cavity: Formalism and application to the hyperfine structure of jet-cooled NO2by saturated-absorption cavity-ring-down spectroscopy

“…It was first observed in gas lasers and was seen as an undesirable effect [1][2][3][4][5]. Then it was promoted as a very convenient technique to get around Doppler broadening [6] and has become a noteworthy implement for metrology and high-resolution spectroscopy purposes [7][8][9]. However, because it is basically a nonlinear process requiring distinction of at least two components of the electromagnetic (EM) field, the determination of the intensity and shape of the transitions requires, one way or another, a nonlinear susceptibility tensor component to be calculated.…”

Absolute frequency measurements and hyperfine structures of the molecular iodine transitions at 578 nm

“…For example, the high frequency stability of an I 2 -stabilized Nd:YAG laser near 532 nm has made it possible to perform precision measurements of hyperfine splittings and made an accurate determination of the hyperfine constants. These studies have revealed the rotation dependence of electric quadrupole hyperfine constants [29,30], and the vibration dependence of tensor spin-spin and scalar spin-spin hyperfine constants [31]. Here we deduce the hyperfine constants of the observed four rovibrational transitions at 578 nm by employing a similar theoretical fit.…”

“…In this fit, the hyperfine constants in the excited state eQq , C , d , and δ were treated as free parameters. The ground-state constant eQq was tentatively estimated using a formula describing the J dependence of eQq with v = 0 [29]. The other groundstate constants C , d , and δ were fixed to the values for v = 0 given in Ref.…”

Quadrupole interaction in the solid halogens—a new (not final) look

“…For I 2 recent laser spectroscopy has produced a value of extreme accuracy for the vibrational ground state [8], while for Br 2 an older result of much less precision exists [9]. In the case of Cl 2 the coupling constant has been determined from the analysis of spectroscopic data of the Cl 2 -Ar van-der-Waals complex [10].…”