A revised rotation-vibration line list for the combined hydrogen cyanide (HCN)/hydrogen isocyanide (HNC) system is presented. The line list uses ab initio transition intensities calculated previously ...and extensive data sets of recently measured experimental energy levels. The resulting line list has significantly more accurate wavelengths than previous ones for these systems. An improved value for the separation between HCN and HNC is adopted, leading to an approximately 25 per cent lower predicted thermal population of HNC as a function of temperature in the key 2000 to 3000 K region. Temperature-dependent partition functions and equilibrium constants are presented. The line lists are validated by comparison with laboratory spectra and are presented in full as supplementary data to the article and at www.exomol.com.
•Line lists for 80 molecules and 190 isotopologues totaling 700 billion transition.•Partition functions, state lifetimes, cooling functions, Lande g-factors, cross sections, opacities, pressure ...broadening parameters, k-coeffcients and dipoles also provided.•Implementation of higher resolution line llsts based on the MARVEL protocol.
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The ExoMol database (www.exomol.com) provides molecular data for spectroscopic studies of hot atmospheres. While the data are intended for studies of exoplanets and other astronomical bodies, the dataset is widely applicable. The basic form of the database is extensive line lists; these are supplemented with partition functions, state lifetimes, cooling functions, Landé g-factors, temperature-dependent cross sections, opacities, pressure broadening parameters, k-coefficients and dipoles. This paper presents the latest release of the database which has been expanded to consider 80 molecules and 190 isotopologues totaling over 700 billion transitions. While the spectroscopic data are concentrated at infrared and visible wavelengths, ultraviolet transitions are being increasingly considered in response to requests from observers. The core of the database comes from the ExoMol project which primarily uses theoretical methods, albeit usually fine-tuned to reproduce laboratory spectra, to generate very extensive line lists for studies of hot bodies. The data have recently been supplemented by line lists derived from direct laboratory observations, albeit usually with the use of ab initiotransition intensities. A major push in the new release is towards accurate characterisation of transition frequencies for use in high resolution studies of exoplanets and other bodies.
Photoisomerization of a highly active Ru water oxidation catalyst, d-Ru(tpy)(pynap)OH22+, into an inactive p-form was notably hindered by attachment onto metal oxide electrodes though a phosphonate ...anchoring group. This increased photostability allowed for photoelectrochemical and mechanistic studies of the catalyst when attached onto FTO, nanoITO, and WO3 electrodes. The redox and catalytic activity of the catalyst was found to be unaffected by surface-binding. This approach may open opportunities to investigate other unstable homogeneous catalysts for water splitting.
•Ru water oxidation catalysts were successfully attached onto oxide electrodes.•Surface bound Ru catalysts exhibit the same redox properties as in solution.•Photoisomerization of the active Ru catalyst was hindered by surface-binding.•A WO3 photoanode with the catalyst showed enhanced photoelectrochemical activity.
Surface-binding of molecular water oxidation catalysts through phosphonated ligands offers a promising strategy for attaching homogeneous catalysts onto conductive or semiconductive oxide surfaces for heterogeneous catalysis. In this work, the highly active Ru(tpy)(pynap)OH22+ (tpy=2,2′:6′,2″-terpyridine; pynap=2-(pyrid-2′-yl)-1,8-naphthyridine) water oxidation catalyst is attached onto metal oxide electrodes through a phosphate group. Electrochemical and photoelectrochemical results confirm that ruthenium oxidation chemistries and water oxidation proficiency remain largely unaffected by phosphonation. Surface-binding reveals minimal photoisomerization of the active d-form and allows us to evaluate photoelectrochemical and mechanistic properties of the catalyst. Spectroelectrochemical experiments support the evolution of multiple ruthenium oxidation states in agreement with Pourbaix diagrams. Although photoisomerization of d-Ru(H2PO3-tpy)(pynap)OH22+ is considerably hindered when the catalyst is attached onto a rigid oxide electrode, surface desorption remains a major challenge.
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•ExoMol provides comprehensive spectroscopic data for key molecules.•The ExoMol data structure is defined.•A summary of present and future contents of the database is given.
The ...ExoMol database (www.exomol.com) provides extensive line lists of molecular transitions which are valid over extended temperature ranges. The status of the current release of the database is reviewed and a new data structure is specified. This structure augments the provision of energy levels (and hence transition frequencies) and Einstein A coefficients with other key properties, including lifetimes of individual states, temperature-dependent cooling functions, Landé g-factors, partition functions, cross sections, k-coefficients and transition dipoles with phase relations. Particular attention is paid to the treatment of pressure broadening parameters. The new data structure includes a definition file which provides the necessary information for utilities accessing ExoMol through its application programming interface (API). Prospects for the inclusion of new species into the database are discussed.
The HITRAN2020 molecular spectroscopic database Gordon, I.E.; Rothman, L.S.; Hargreaves, R.J. ...
Journal of Quantitative Spectroscopy & Radiative Transfer/Journal of quantitative spectroscopy & radiative transfer,
01/2022, Letnik:
277
Journal Article
Recenzirano
Odprti dostop
•The HITRAN2020 molecular spectroscopic database and its validations are presented.•Extended line-by-line coverage to 55 molecules, with new isotopologues included.•Increased spectral and dynamic ...ranges for multiple molecules.•Quality and amount of spectral parameters (including sophisticated line shapes) is increased.•Updates to cross sections, CIA, software tools & auxiliary data also described.
The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years).
All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules.
The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition.
A global potential energy surface for H3 Mizus, Irina I.; Polyansky, Oleg L.; McKemmish, Laura K. ...
Molecular physics,
07/2019, Letnik:
117, Številka:
13
Journal Article
Recenzirano
Odprti dostop
A globally correct potential energy surface (PES) for the
molecular ion is presented. The Born-Oppenheimer (BO) ab initio grid points of Pavanello et al. J. Chem. Phys. 136, 184303 (2012) are ...refitted as BOPES75K, which reproduces the energies below dissociation with a root mean square deviation of 0.05 cm
−1
; points between dissociation and 75,000 cm
−1
are reproduced with the average accuracy of a few wavenumbers. The new PES75K+ potential combines BOPES75K with adiabatic, relativistic and quantum electrodynamics (QED) surfaces to provide the most accurate representation of the
global potential to date, overcoming the limitations on previous high accuracy
PESs near and above dissociation. PES75K+ can be used to provide predictions of bound rovibrational energy levels with an accuracy of approaching 0.1 cm
−1
. Calculation of rovibrational energy levels within PES75K+ suggests that the non-adiabatic correction remains a limiting factor. The PES is also constructed to give the correct asymptotic limit making it suitable for use in studies of the
prototypical chemical reaction. An improved dissociation energy for
is derived as
cm
−1
.
The HITRAN2016 molecular spectroscopic database Gordon, I.E.; Rothman, L.S.; Hill, C. ...
Journal of Quantitative Spectroscopy & Radiative Transfer/Journal of quantitative spectroscopy & radiative transfer,
12/2017, Letnik:
203
Journal Article
Recenzirano
Odprti dostop
•HITRAN2016 molecular spectroscopic database is described.•Dynamic web interface at www.hitran.org is introduced.•HITRAN Application Programming Interface is introduced.•Substantial extent of the ...amount and quality of the data highlighted.•Many new spectroscopic parameters are now available in HITRAN.
This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.
A global potential energy surface for H 3 Mizus, Irina I.; Polyansky, Oleg L.; McKemmish, Laura K. ...
Molecular physics,
07/2019, Letnik:
117, Številka:
13
Journal Article
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