Accurate prediction of the ammonia probes of a variable proton-to-electron mass ratio

作者：Owens A^*; Yurchenko S N; Thiel W; Spirko V

来源：Monthly Notices of the Royal Astronomical Society, 2015, 450(3): 3191-3200.

DOI：10.1093/mnras/stv869

• molecular data
• cosmological parameters
• infrared: ISM
• submillimetre: ISM

A comprehensive study of the mass sensitivity of the vibration-rotation-inversion transitions of (NH3)-N-14, (NH3)-N-15, (ND3)-N-14 and (ND3)-N-15 is carried out variationally using the trove approach. Variational calculations are robust and accurate, offering a new way to compute sensitivity coefficients. Particular attention is paid to the Delta k = +/- 3 transitions between the accidentally coinciding rotation-inversion energy levels of the nu(2) = 0(+), 0(-), 1(+) and 1(-) states, and the inversion transitions in the nu(4) = 1 state affected by the 'giant' l-type doubling effect. These transitions exhibit highly anomalous sensitivities, thus appearing as promising probes of a possible cosmological variation of the proton-to-electron mass ratio mu. Moreover, a simultaneous comparison of the calculated sensitivities reveals a sizeable isotopic dependence which could aid an exclusive ammonia detection.

• 出版日期2015-7-1