<i>Der römische Genius</i>. By Hille Kunckel.

Kleiner, Diana E. E.; Kleiner, Fred S.; Kunckel, Hille

doi:10.2307/503197

Cited by 5 publications

(7 citation statements)

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“…The basic theory of the non-rigid tops with internal rotation was established in the 1950s [87,88] and the main features of the methanol spectrum were explained. Later on the theory was refined many times and currently there is a very impressive agreement between the theory and experiment [89][90][91][92].…”

Section: Molecules With Hindered Rotation: Methanol and Methylaminementioning

confidence: 99%

Microwave and submillimeter molecular transitions and their dependence on fundamental constants

Kozlov

Levshakov

2013

Annalen der Physik

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Microwave and submillimeter molecular transition frequencies between nearly degenerated rotational levels, tunneling transitions, and mixed tunneling-rotational transitions show an extremely high sensitivity to the values of the finestructure constant, α, and the electron-to-proton mass ratio, μ. This review summarizes the theoretical background on quantum-mechanical calculations of the sensitivity coefficients of such transitions to tiny changes in α and μ for a number of molecules which are usually observed in Galactic and extragalactic sources, and discusses the possibility of testing the space-and time-invariance of fundamental constants through comparison between precise laboratory measurements of the molecular rest frequencies and their astronomical counterparts. In particular, diatomic radicals CH, OH, NH + , and a linear polyatomic radical C 3 H in electronic ground state, polyatomic molecules NH 3 , ND 3 , NH 2 D, NHD 2 , H 2 O 2 , H 3 O + , CH 3 OH, and CH 3 NH 2 in their tunneling and tunneling-rotational modes are considered. It is shown that sensitivity coefficients strongly depend on the quantum numbers of the corresponding transitions. This can be used for astrophysical tests of Einstein's Equivalence Principle all over the Universe at an unprecedented level of sensitivity of ∼10 −9 , which is a limit three to two orders of magnitude lower as compared to the current constraints on cosmological variations of α and μ: α/α < 10 −6 , μ/μ < 10 −7 .

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Section: Molecules With Hindered Rotation: Methanol and Methylaminementioning

confidence: 99%

Microwave and submillimeter molecular transitions and their dependence on fundamental constants

Kozlov

Levshakov

2013

Annalen der Physik

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“…The basic theory of the non-rigid tops with internal rotation was established in the fifties (Lin & Swalen 1959;Herschbach 1959) and the main features of the methanol spectrum were explained. Later on the theory was refined many times and currently there is a very impressive agreement between the theory and experiment (Anderson et al 1990;Müller et al 2006;Xu et al 2008;Kleiner 2010).…”

Section: Introductionmentioning

confidence: 99%

Methanol as a Tracer of Fundamental Constants

Levshakov

Kozlov

Reimers

2011

ApJ

103

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The methanol molecule CH 3 OH has a complex microwave spectrum with a large number of very strong lines. This spectrum includes purely rotational transitions as well as transitions with contributions of the internal degree of freedom associated with the hindered rotation of the OH group. The latter takes place due to the tunneling of hydrogen through the potential barriers between three equivalent potential minima. Such transitions are highly sensitive to changes in the electron-to-proton mass ratio, µ = m e /m p , and have different responses to µ-variations. The highest sensitivity is found for the mixed rotation-tunneling transitions at low frequencies. Observing methanol lines provides more stringent limits on the hypothetical variation of µ than ammonia observation with the same velocity resolution. We show that the best quality radio astronomical data on methanol maser lines constrain the variability of µ in the Milky Way at the level of |∆µ/µ| < 28 × 10 −9 (1σ) which is in line with the previously obtained ammonia result, |∆µ/µ| < 29 × 10 −9 (1σ). This estimate can be further improved if the rest frequencies of the CH 3 OH microwave lines will be measured more accurately.

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“…31 In the case of a small A-E splitting they require a very large torsional basis set. In the previous investigation of Roucou et al, 13 BELGI-Cs-hyperfine 30 and XIAM 31,32 failed to reproduce the FTMW spectrum of mononitrotoluene with experimental accuracy.…”

Section: Internal Rotation Modelingmentioning

confidence: 89%

“…This IAM treatment turns out to be numerically more stable than similar treatments designed to account for the internal rotation of a methyl group and relying on the diagonalization of a torsional Hamiltonian. Such approaches include those introduced a long time ago by Herbst et al, 29 BELGI-Cs-hyperfine, 30 and XIAM. 31 In the case of a small A-E splitting they require a very large torsional basis set.…”

Section: Internal Rotation Modelingmentioning

confidence: 99%