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Molecular line data for the rotational transitions of a number of astrophysically interesting species have been collected and are made publically available through the www. These data, including energy levels, statistical weights, Einstein…

Astrophysics · Physics 2007-05-23 F. L. Schoeier , F. F. S. van der Tak , E. F. van Dishoeck , J. H. Black

Elaborating on a formalism that was first expressed some 40 years ago, we consider the brightness of low-lying mm-wave rotational lines of strongly polar molecules at the threshold of detectability. We derive a simple expression relating…

Astrophysics of Galaxies · Physics 2016-06-08 Harvey Liszt , Jerome Pety

Accurate line lists are important for the description of the spectroscopic nature of small molecules. While a line list for CN (an important molecule for chemistry and astrophysics) exists, no underlying energy spectroscopic model has been…

Chemical Physics · Physics 2021-06-08 Anna-Maree Syme , Laura K. McKemmish

An accurate and comprehensive room temperature rotation-vibration transition line list for phosphine (31PH3) is computed using a newly refined potential energy surface and a previously constructed ab initio electric dipole moment surface.…

Earth and Planetary Astrophysics · Physics 2013-05-17 Clara Sousa-Silva , Sergei N. Yurchenko , Jonathan Tennyson

In this paper we discuss two approximate methods previously suggested for modeling hyperfine spectral line emission for molecules whose collisional transitions rates between hyperfine levels are unknown. Hyperfine structure is seen in the…

Astrophysics of Galaxies · Physics 2015-05-18 Eric Keto , George Rybicki

We present the easy-to-use, publicly available, Python package petitRADTRANS, built for the spectral characterization of exoplanet atmospheres. The code is fast, accurate, and versatile; it can calculate both transmission and emission…

Earth and Planetary Astrophysics · Physics 2019-07-23 P. Mollière , J. P. Wardenier , R. van Boekel , Th. Henning , K. Molaverdikhani , I. A. G. Snellen

Any future detection of the calcium monohydroxide radical (CaOH) in stellar and exoplanetary atmospheres will rely on accurate molecular opacity data. Here, we present the first comprehensive molecular line list of CaOH covering the \A--\X\…

Earth and Planetary Astrophysics · Physics 2022-10-25 Alec Owens , Alexander Mitrushchenkov , Sergei N. Yurchenko , Jonathan Tennyson

A comprehensive, calculated line list of frequencies and transition probabilities for the singly deuterated isotopologue of H3+, H2D+, is presented. The line list, called ST1, contains over 22 million rotational-vibrational transitions…

Computational Physics · Physics 2010-05-11 Taha Sochi , Jonathan Tennyson

A new molecular line list for lithium hydroxide ($^{7}$Li$^{16}$O$^{1}$H) covering wavelengths $\lambda > 1 \mu$m (the 0-10000 cm$^{-1}$ range) is presented. The OYT7 line list contains over 331 million transitions between…

Remote sensing experiments require high-accuracy, preferably sub-percent, line intensities and in response to this need we present computed room temperature line lists for six symmetric isotopologues of carbon dioxide: $^{13}$C$^{16}$O$_2$,…

Earth and Planetary Astrophysics · Physics 2017-11-01 Emil J. Zak , Jonathan Tennyson , Oleg L. Polyansky , Lorenzo Lodi , Nikolay F. Zobov , Sergei A. Tashkun , Valery I. Perevalov

ExoMolHR is an empirical, high-resolution molecular spectrum calculator for the high-temperature molecular line lists available from the ExoMol molecular database. Uncertainties, where available, in recommended ExoMol datasets are used to…

Earth and Planetary Astrophysics · Physics 2025-04-16 Jingxin Zhang , Christian Hill , Jonathan Tennyson , Sergei N. Yurchenko

A variationally computed $^{28}$SiH$_4$ rotation-vibration line list applicable for temperatures up to $T=1200\,$K is presented. The line list, called OY2T, considers transitions with rotational excitation up to $J=42$ in the wavenumber…

Chemical Physics · Physics 2017-12-29 A. Owens , A. Yachmenev , W. Thiel , J. Tennyson , S. N. Yurchenko

We describe a code designed for hot media {(T $\ge$} a few 10$^4$ K), optically thick to Compton scattering. It computes the structure of a plane-parallel slab of gas in thermal and ionization equilibrium, illuminated on one side or on both…

Astrophysics · Physics 2009-09-25 Anne-Marie Dumont , Suzy Collin

Accurate line lists for the carbon dimer, C$_2$, are presented. These line lists cover rovibronic transitions between the eight lowest electronic states: $X\,{}^{1}\Sigma_{g}^{+}$, $a\,{}^{3}\Pi_{u}$, $A\,{}^{1}\Pi_{u}$,…

Solar and Stellar Astrophysics · Physics 2018-12-19 Sergei N. Yurchenko , István Szabó , Elizaveta Pyatenko , Jonathan Tennyson

In this paper we present two efficient implementations of the diffusion approximation to be employed in Monte Carlo computations of radiative transfer in dusty media of massive circumstellar disks. The aim is to improve the accuracy of the…

Instrumentation and Methods for Astrophysics · Physics 2009-11-13 M. Min , C. P. Dullemond , C. Dominik , A. de Koter , J. W. Hovenier

Atmospheric carbon dioxide concentrations are being closely monitored by remote sensing experiments which rely on knowing line intensities with an uncertainty of 0.5% or better. We report a theoretical study providing rotation-vibration…

We present a numerical method and computer code to calculate the radiative transfer and excitation of molecular lines. Formulating the Monte Carlo method from the viewpoint of cells rather than photons allows us to separate local and…

Astrophysics · Physics 2007-05-23 Michiel R. Hogerheijde , Floris F. S. van der Tak

We develop a method of analyzing radio frequency spectral line observations to derive data on the temperature, density, velocity, and molecular abundance of the emitting gas. The method incorporates a radiative transfer code with a new…

Astrophysics · Physics 2009-11-10 Eric Keto , George B. Rybicki , Edwin A. Bergin , Rene Plume

As state of the art neural networks (NNs) continue to grow in size, their resource-efficient implementation becomes ever more important. In this paper, we introduce a compression scheme that reduces the number of computations required for…

Machine Learning · Computer Science 2025-04-25 Hans Rosenberger , Rodrigo Fischer , Johanna S. Fröhlich , Ali Bereyhi , Ralf R. Müller

The best molecular line lists for astrophysical applications today require both high accuracy of line positions for strong lines as well as high overall completeness. The former is required to enable, for example, molecular detection in…