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Related papers: Methyl mercaptan (CH3SH) as a probe for $\mu$ vari…

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Methyl mercaptan (CH$_3$SH) is an important sulfur-bearing species in the interstellar medium, terrestrial environment, and potentially in planetary atmospheres. The aim of the present study is to provide accurate spectroscopic parameters…

Differential measurements of the fundamental constant mu = m_e/m_p (the electron-to-proton mass ratio) for two sources near the Galactic Center - the Sgr B2(N) and B2(M) molecular clouds - suggest that mu is lower in these clouds than its…

Astrophysics of Galaxies · Physics 2025-11-04 J. S. Vorotyntseva , S. A. Levshakov , C. Henkel

The methanol molecule is a sensitive probe of astrochemistry, astrophysics, and fundamental physics. The first-principles elucidation and prediction of its rotation-torsional-vibrational motions are enabled in this work by the computation…

Chemical Physics · Physics 2025-08-05 Ayaki Sunaga , Tibor Győri , Gábor Czakó , Edit Matyus

We study the sensitivity of the microwave and submillimeter transitions of the isotopologues of hydronium to the variation of the electron-to-proton mass ratio mu. These sensitivities are enhanced for the low frequency mixed…

Atomic Physics · Physics 2011-06-03 M. G. Kozlov , S. G. Porsev , D. Reimers

Molecular overtone transitions provide optical frequency transitions sensitive to variation in the proton-to-electron mass ratio ($\mu\equiv m_p/m_e$). However, robust molecular state preparation presents a challenge critical for achieving…

Among all closed-shell species observed in molecular clouds, molecules with C$_{3v}$ symmetry play a crucial role, as their rotational spectroscopy allows them to behave as a gas thermometer. In the interstellar medium, methyl cyanide…

Astrophysics of Galaxies · Physics 2023-09-22 M. Ben Khalifa , P. J. Dagdigian , J. Loreau

Experimental techniques to manipulate cold molecules have seen great development in recent years. The precision measurements of cold molecules are expected to give insights into fundamental physics. We use a rovibrationally pure sample of…

Atomic Physics · Physics 2019-08-26 Jun Kobayashi , Atsushi Ogino , Shin Inouye

Reported here are portions of the infrared absorption cross-section for methanol (CH$_3$OH) as measured by frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) at wavelengths near $\lambda$ = 2.0 $\mu$m. High-resolution spectra of…

Chemical Physics · Physics 2019-12-10 Hongming Yi , Adam J. Fleisher

A robust variational approach is used to investigate the sensitivity of the rotation-vibration spectrum of phosphine (PH$_3$) to a possible cosmological variation of the proton-to-electron mass ratio, $\mu$. Whilst the majority of computed…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-17 Alec Owens , Sergei N. Yurchenko , Vladimir Špirko

We report deep Green Bank Telescope (GBT) spectroscopy in the redshifted NH$_3$~(1,1), CS~1-0 and H$_2$CO~0$_{\rm 00}$-1$_{\rm 01}$ lines from the $z \sim 0.685$ absorber towards B0218+357. The inversion (NH$_3$) and rotational (CS,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Nissim Kanekar

We have started a measurement campaign of numerous methanol isotopologs in low-lying torsional states in order to provide extensive line lists for radio astronomical observations from an adequate spectroscopic model and to investigate how…

New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH…

Astrophysics of Galaxies · Physics 2015-06-18 L. Kolesniková , B. Tercero , J. Cernicharo , J. L. Alonso , A. M. Daly , B. P. Gordon , S. T. Shipman

Methanol (CH$_{3}$OH) is a key complex organic molecule (COM) in the interstellar medium, widely used as a tracer of dense gas and hot molecular cores (HMCs). Using high-resolution ALMA observations from the ATOMS survey, we investigate the…

The aim of the presented work is to analyze the impact of experimentally evaluated reactions of hydrogen abstraction on surfaces of interstellar grains on the chemical evolution of methanol and its precursors on grains and in the gas phase…

Astrophysics of Galaxies · Physics 2021-03-24 V. A. Sokolova

We report the detection of methyl ketene towards TMC-1 with the QUIJOTE line survey. Nineteen rotational transitions with rotational quantum numbers ranging from J = 3 up to J = 5 and Ka =< 2 were identified in the frequency range 32.0-50.4…

Small polycyclic aromatic hydrocarbons and somewhat larger cyano derivatives were detected in the cold dark cloud TMC-1 recently. Their formation from smaller hydrocarbons is not well understood, in part because abundances of many species…

Astrophysics of Galaxies · Physics 2026-02-02 Holger S. P. Müller , Frank Lewen , Jean-Claude Guillemin , Stephan Schlemmer

Relative permittivities at 1 MHz, $\varepsilon_{\text{r}}$, at 0.1 MPa and (293.15-303.15) K and refractive indices, $n_{\text{D}}$, at similar conditions have been measured for the alkan-1-ol (methanol, propan-1-ol, butan-1-ol, pentan-1-ol…

A spectral survey of methyl acetylene (CH3CCH) was conducted toward the hot molecular core/outflow G331.512-0.103. Our APEX observations allowed the detection of 41 uncontaminated rotational lines of CH3CCH in the frequency range between…

The methoxy radical, CH$_3$O, has long been studied experimentally and theoretically by spectroscopists because it displays a weak Jahn-Teller effect in its electronic ground state, combined with a strong spin-orbit interaction. In this…

We present 247-GHz molecular line observations of methanol (CH$_3$OH) toward sixteen massive star-forming regions, using the APEX telescope with an angular resolution of $25''$. The sample covers a range of evolutionary states, including…