Sensitivity to proton-to-electron mass ratio variation from pairs of isotopic lithium hydride rotational and rovibrational transitions

Florin Lucian Constantin (1)

1 PhLAM - Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523

Calculations of the sensitivities of rotational and rovibrational transitions of isotopic lithium hydride in the electronic ground state to a variation of the proton-to-electron mass ratio constant are presented. A highly enhanced sensitivity coefficient is observed for the splitting of near resonant transitions arising from a cancellation between rotational intervals and frequency shifts associated respectively to the isotope effect, to the anharmonicity and to the rotation-vibration interaction. It ranges from 73 748.47(1) to −21 672(137) for the transitions with low to intermediate rotational quantum numbers in the lowest vibrational energy levels. The splittings of rotational transitions of 7LiD in the vibrational level v = 0 and 6LiD in the vibrational level v = 2 have a sensitivity coefficient of ∼−3 for J up to 29 and that of 6LiH R(0) and 7LiH R(1) rovibrational transitions in the v = 0 − >1 band has a sensitivity coefficient of −585. The approach allowed comparison of frequency intervals between rotational lines with ammonia inversion lines detected in the microwave spectra of B0218 + 367 quasar to put constraints to a variation of the proton-to-electron mass ratio.

Domaines: Chimie-Physique [physics.chem-ph]

Florin Lucian Constantin. Sensitivity to proton-to-electron mass ratio variation from pairs of isotopic lithium hydride rotational and rovibrational transitions. Journal of Physics B: Atomic, Molecular and Optical Physics, 2015, 48 (17), pp.175006. ⟨10.1088/0953-4075/48/17/175006⟩. ⟨hal-03335683⟩