The ExoMol project: Software for computing large molecular line lists

Tennyson, Jonathan; Yurchenko, Sergei N.

doi:10.1002/qua.25190

Cited by 77 publications

(96 citation statements)

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“…These systems have been treated within the ExoMol framework19 and we refer the reader to the relevant publications for details of the ro-vibrational calculations51525354. Candidate ro-vibrational states were identified by sorting the files according to upper state energy.…”

Section: Resultsmentioning

confidence: 99%

Simulating electric field interactions with polar molecules using spectroscopic databases

Owens

Żak

Chubb

et al. 2017

Sci Rep

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Ro-vibrational Stark-associated phenomena of small polyatomic molecules are modelled using extensive spectroscopic data generated as part of the ExoMol project. The external field Hamiltonian is built from the computed ro-vibrational line list of the molecule in question. The Hamiltonian we propose is general and suitable for any polar molecule in the presence of an electric field. By exploiting precomputed data, the often prohibitively expensive computations associated with high accuracy simulations of molecule-field interactions are avoided. Applications to strong terahertz field-induced ro-vibrational dynamics of PH3 and NH3, and spontaneous emission data for optoelectrical Sisyphus cooling of H2CO and CH3Cl are discussed.

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Section: Resultsmentioning

confidence: 99%

Simulating electric field interactions with polar molecules using spectroscopic databases

Owens

Żak

Chubb

et al. 2017

Sci Rep

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“…1, with the aim of facilitating the solution of the rotation-vibration Schrödinger equation for ethane and related molecules. The MS group G 36 has been the subject of a number of studies (see, for example, [4,5]). The EMS group G 36 (EM) was studied in detail by Di Lauro and Lattanzi [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…The MS group G 36 has been the subject of a number of studies (see, for example, [4,5]). The EMS group G 36 (EM) was studied in detail by Di Lauro and Lattanzi [6,7]. Examples of the application of the G 36 (EM) group include studies of the rotation-torsional spectra of various ethane-type molecules [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…The EMS group G 36 (EM) was studied in detail by Di Lauro and Lattanzi [6,7]. Examples of the application of the G 36 (EM) group include studies of the rotation-torsional spectra of various ethane-type molecules [8][9][10][11][12]. TROVE (Theoretical ROVibrational Energies) [3,13] is a general variational program for computing ro-vibrational spectra and properties for small to medium-size polyatomic molecules of arbitrary structure.…”

Section: Introductionmentioning

confidence: 99%

“…It has been applied to a large number of polyatomic species , most of which have considerable symmetry [e.g., with molecular symmetry groups [1] such as C 3v (M), D nh (M) and T d (M)]. TROVE is an efficient computer program for simulating hot spectra of polyatomic molecules; it is one of the main tools of the ExoMol project [35,36]. The most recent updates of TROVE have been reported in Refs.…”

Section: Introductionmentioning

confidence: 99%

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Transformation Properties under the Operations of the Molecular Symmetry Groups G36 and G36(EM) of Ethane H3CCH3

et al. 2019

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In the present work, we report a detailed description of the symmetry properties of the eight-atomic molecule ethane, with the aim of facilitating the variational calculations of rotation-vibration spectra of ethane and related molecules. Ethane consists of two methyl groups CH 3 where the internal rotation (torsion) of one CH 3 group relative to the other is of large amplitude and involves tunneling between multiple minima of the potential energy function. The molecular symmetry group of ethane is the 36-element group G 36 , but the construction of symmetrized basis functions is most conveniently done in terms of the 72-element extended molecular symmetry group G 36 (EM). This group can subsequently be used in the construction of block-diagonal matrix representations of the ro-vibrational Hamiltonian for ethane. The derived transformation matrices associated with G 36 (EM) have been implemented in the variational nuclear motion program TROVE (Theoretical ROVibrational Energies). TROVE variational calculations will be used as a practical example of a G 36 (EM) symmetry adaptation for large systems with a non-rigid, torsional degree of freedom. We present the derivation of irreducible transformation matrices for all 36 (72) operations of G 36 (M) (G 36 (EM)) and also describe algorithms for a numerical construction of these matrices based on a set of four (five) generators. The methodology presented is illustrated on the construction of the symmetry-adapted representations both of the potential energy function of ethane and of the rotation, torsion and vibration basis set functions.

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Computational challenges in Astrochemistry

Biczysko

Bloino

Puzzarini

2017

WIREs Comput Mol Sci

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Cosmic evolution is the tale of progressive transition from simplicity to complexity. The newborn universe starts with the simplest atoms formed after the Big Bang and proceeds toward ‘astronomical complex organic molecules’ (astroCOMs). Understanding the chemical evolution of the universe is one of the main aims of Astrochemistry, with the starting point being the knowledge whether a molecule is present in the astronomical environment under consideration and, if so, its abundance. However, the interpretation of astronomical detections and the identification of molecules are not all straightforward. In particular, molecular species characterized by large amplitude motions represent a major challenge for molecular spectroscopy and, in particular, for computational spectroscopy. More in general, for flexible systems, the conformational equilibrium needs to be taken into account and accurately investigated. It is shown that crucial challenges in the computational spectroscopy of astroCOMs can be successfully overcome by combining state‐of‐the‐art quantum‐mechanical approaches with ad hoc treatments of the nuclear motion, thus demonstrating that the rotational and vibrational features can be predicted with the proper accuracy. The second key step in Astrochemistry is understanding how astroCOMs are formed and how they chemically evolve toward more complex species. The challenges in the computational chemistry of astroCOMs are related to the derivation of feasible formation routes in the typically harsh conditions (extremely low temperature and density) of the interstellar medium, as well as the understanding of the chemical evolution of small species toward macromolecules. Within the transition state theory, for instance, it is possible to obtain new astrochemical information by identifying the intermediate species and transition states connecting them in a plausible formation route. Depending on the sophistication of the model, different quantities may be needed. Nevertheless, accuracy can be critical, thus requiring state‐of‐the‐art computational approaches to derive geometries, energies, spectroscopic properties, and thermochemical data for each relevant structure along the reaction path. This article is categorized under: Theoretical and Physical Chemistry > Spectroscopy Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

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The ExoMol project: Software for computing large molecular line lists

Cited by 77 publications

References 143 publications

Simulating electric field interactions with polar molecules using spectroscopic databases

Simulating electric field interactions with polar molecules using spectroscopic databases

Transformation Properties under the Operations of the Molecular Symmetry Groups G36 and G36(EM) of Ethane H3CCH3

Computational challenges in Astrochemistry

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