Rotation dependence of the excited-state electric quadrupole hyperfine interaction by high-resolution laser spectroscopy of ^127I_2

Abstract

Hyperfine structures of the R(58)32–0,P(55)32–0, and P(104)34–0 transitions of molecular iodine near 532 nm are measured by heterodyne beating of two I2-stabilized lasers. The measured hyperfine splittings are fitted to a four-term Hamiltonian, which includes the electric quadrupole, spin–rotation, tensor spin–spin, and scalar spin–spin interactions, with an accuracy of ∼600 Hz for the R(58)32–0 and P(55)32–0 transitions. Highly accurate hyperfine constants are obtained from this fit. The rotation dependence of the excited state (the B state, v′=32) electric quadrupole constant eQq′ is found to be eQq′(J)=-544.049(14)-0.0002110(43)J(J+1) MHz. The observed hyperfine transitions are good candidates for an optical frequency reference in the 532-nm region.