Rotation dependence of the excited-state electric quadrupole hyperfine interaction by high-resolution laser spectroscopy of I-127(2)

Hyperfine structures of the R(58)32-0, P(55) 32-0, and P(104)34-0 transitio ns of molecular iodine near 532 mn are measured by heterodyne beating of tw o I-2-Stabilized lasers. The measured hyperfine splittings are fitted to a four-term Hamiltonian, which includes the electric quadrupole, spin-rotatio n, tensor spin-spin, and scalar spin-spin interactions, with an accuracy of similar to 600 Hz for the R(58)32-0 and P(55)32-0 transitions. Highly accu rate hyperfine constants are obtained from this fit. The rotation dependenc e 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. (C) 2001 Optical Society of America.