Rotational spectrum of molecular ion NH^+ as a probe for alpha- and m_e/m_p-variation

Abstract

We identify the molecular ion NH^+ as a potential candidate for probing variations in the fine structure constant alpha and electron-to-proton mass ratio mu. NH^+ has an anomalously low-lying excited Sigma state, being only a few hundred cm^-1 above the ground Pi state. Being a light molecule, this proximity is such that rotational levels of the respective states are highly intermixed for low angular momenta. We find that several low-frequency transitions within the collective rotational spectrum experience enhanced sensitivity to alpha- and mu-variation. This is attributable to the close proximity of the Pi and Sigma states, as well as the ensuing strong spin-orbit coupling between them. Suggestions that NH^+ may exist in interstellar space and recent predictions that trapped-ion precision spectroscopy will be adaptable to molecular ions make NH^+ a promising system for future astrophysical and laboratory studies of alpha- and mu-variation.

8 pages, 1 figure

References in corpus (18)

• Precision Test of Mass Ratio Variations with Lattice-Confined Ultracold Molecules
• Enhanced effect of temporal variation of the fine structure constant in diatomic molecules
• Enhanced sensitivity to variation of the fine structure constant and m_p/m_e in diatomic molecules
• Stability of the proton-to-electron mass ratio
• Enhanced laboratory sensitivity to variation of the fine-structure constant using highly-charged ions
• Enhanced sensitivity to variation of $m_e/m_p$ in molecular spectra
• Enhanced sensitivity to time-variation of m_p/m_e in the inversion spectrum of ammonia
• Constraining changes in the proton-electron mass ratio with inversion and rotational lines
• Hydrides in Young Stellar Objects: Radiation tracers in a protostar-disk-outflow system
• Comment on "Limits on the Time Variation of the Electromagnetic Fine-Structure Constant in the Low Energy Limit from Absorption Lines in the Spectra of Distant Quasars"
• First measurement of Mg isotope abundances at high redshifts and accurate estimate of Delta alpha/alpha
• Enhanced effect of quark mass variation in 229Th and limits from Oklo data
• On Th229 and time-dependent fundamental constants
• $\Lambda$-doublet spectra of diatomic radicals and their dependence on fundamental constants
• Sensitivity of the H3O+ inversion-rotational spectrum to changes in m_e/m_p
• Coulomb energy contribution to the excitation energy in ${}^{229}$Th and enhanced effect of $\alpha$ variation
• Enhanced Sensitivity to the Time Variation of the Fine-Structure Constant and $m_p/m_e$ in Diatomic Molecules: A Closer Examination of Silicon Monobromide
• Sensitivity of the isotopologues of hydronium to variation of the electron-to-proton mass ratio

Cited by in corpus (17)

• Preparation and coherent manipulation of pure quantum states of a single molecular ion
• Perspective: Tipping the scales - search for drifting constants from molecular spectra
• Quantum non-demolition state detection and spectroscopy of single trapped molecules
• Efficient sympathetic motional ground-state cooling of a molecular ion
• Microwave and submillimeter molecular transitions and their dependence on fundamental constants
• High sensitivity to mass-ratio variation in deep molecular potentials
• Sensitivity of rotational transitions in CH and CD to a possible variation of fundamental constants
• Modular cryostat for ion trapping with surface-electrode ion traps
• Two-photon vibrational transitions in ${\mathrm{O}}_2^{+}$ as probes of variation of the proton-to-electron mass ratio
• Cosmological Evolution of Fundamental Constants: From Theory to Experiment
• Microwave quantum logic spectroscopy and control of molecular ions
• Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)
• Linear polyatomic molecules with Π ground state: sensitivity to variation of the fundamental constants
• Diatomic rovibronic transitions as potential probes for proton-to-electron mass ratio across cosmological time
• SeD Radical: A probe for measurement of time variation of Fine Structure Constant($\alpha$) and Proton to Electron Mass Ratio($\mu$)
• Bloch-Siegert shift in application to the astrophysical determination of the fundamental constants variation
• Photon Recoil Spectroscopy: Systematic Shifts and Nonclassical Enhancements