{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:35:40Z","timestamp":1760146540627,"version":"build-2065373602"},"reference-count":42,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2024,11,15]],"date-time":"2024-11-15T00:00:00Z","timestamp":1731628800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT\/MCTES Portugal","award":["LA\/P\/0008\/ 2020; DOI: 10.54499\/LA\/P\/0008\/2020","UIDB\/50006\/2020; DOI: 10.54499\/ UIDB\/50006\/2020"],"award-info":[{"award-number":["LA\/P\/0008\/ 2020; DOI: 10.54499\/LA\/P\/0008\/2020","UIDB\/50006\/2020; DOI: 10.54499\/ UIDB\/50006\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Computation"],"abstract":"<jats:p>In this paper, I present Diatomic, an open-source Excel application that calculates molar thermodynamic properties for diatomic ideal gases. This application is very easy to use and requires only a limited number of molecular constants, which are freely available online. Despite its simplicity, Diatomic provides methodologies and results that are usually unavailable in general quantum chemistry packages. This application uses the general formalism of statistical mechanics, enabling two models to describe the rotational structure and two models to describe the vibrational structure. In this work, Diatomic was used to calculate standard molar thermodynamic properties for a set of fifteen diatomic ideal gases. A special emphasis was placed on the analysis of four properties (standard molar enthalpy of formation, molar heat capacity at constant pressure, average molar thermal enthalpy, and standard molar entropy), which were compared with experimental values. A molecular interpretation for the molar heat capacity at constant pressure, as an interesting pedagogical application of Diatomic, was also explored in this paper.<\/jats:p>","DOI":"10.3390\/computation12110229","type":"journal-article","created":{"date-parts":[[2024,11,15]],"date-time":"2024-11-15T04:47:17Z","timestamp":1731646037000},"page":"229","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Diatomic: An Open-Source Excel Application to Calculate Thermodynamic Properties for Diatomic Molecules"],"prefix":"10.3390","volume":"12","author":[{"given":"Andr\u00e9","family":"Melo","sequence":"first","affiliation":[{"name":"LAQV@REQUIMTE, Departamento de Qu\u00edmica e Bioqu\u00edmica, Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1449","DOI":"10.1351\/pac199163101449","article-title":"Thermodynamic properties of gas phase species of importance to ozone depletion","volume":"63","author":"Abramowitz","year":"1991","journal-title":"Pure Appl. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1007\/s11224-022-02007-w","article-title":"Ab initio studies on complexes of ozone with diatomic molecules","volume":"34","author":"Grein","year":"2023","journal-title":"Struct. Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1146\/annurev.astro.38.1.427","article-title":"Organic molecules in the interstellar medium, comets, and meteorites: A voyage from dark clouds to the early Earth","volume":"38","author":"Ehrenfreund","year":"2000","journal-title":"Annu. Rev. Astron. Astrophys."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"052814","DOI":"10.1103\/PhysRevA.109.052814","article-title":"Diatomic molecules of alkali-metal and alkaline-earth-metal atoms: Interaction potentials, dipole moments, and polarizabilities","volume":"109","author":"Ladjimi","year":"2024","journal-title":"Phys. Rev. A"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"114111","DOI":"10.1063\/1.2835612","article-title":"High-accuracy extrapolated ab initio thermochemistry. III. Additional improvements and overview","volume":"128","author":"Harding","year":"2008","journal-title":"J. Chem. Phys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"184109","DOI":"10.1063\/5.0069322","article-title":"Elaborated thermochemical treatment of HF, CO, N2, and H2O: Insight into HEAT and its extensions","volume":"155","author":"Thorpe","year":"2021","journal-title":"J. Chem. Phys."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"9260","DOI":"10.1021\/acs.jctc.3c01060","article-title":"DAPD Set of Pd-Containing Diatomic Molecules: Accurate Molecular Properties and the Great Lengths to Obtain Them","volume":"19","author":"Chan","year":"2023","journal-title":"J. Chem. Theor. Comput."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"246","DOI":"10.1007\/s10773-023-05494-7","article-title":"Topological Effects on Relativistic Energy Spectra of Diatomic Molecules Under the Magnetic Field with Kratzer Potential and Thermodynamic-Optical Properties","volume":"62","author":"Permatahati","year":"2023","journal-title":"Int. J. Theor. Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1007\/s00214-020-02674-0","article-title":"Rotational thermodynamic parameters for symmetric-top, linear-top and spherical-top molecules: Classical versus quantum approach and New analytical partition functions","volume":"139","author":"Djefoulna","year":"2020","journal-title":"Theor. Chem. Acc."},{"key":"ref_10","unstructured":"Hehre, W.J., Radom, L., Schleyer, P.v.R., and Pople, J.A. (1986). Ab Initio Molecular Orbital Theory, John Wiley."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"7204","DOI":"10.1021\/jp0257810","article-title":"Beyond the Harmonic Approximation: Impact of Anharmonic Molecular Vibrations on the Thermochemistry of Silicon Hydrides","volume":"106","author":"Katzer","year":"2002","journal-title":"J. Phys. Chem. A"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"154112","DOI":"10.1063\/1.3504614","article-title":"Hindered rotor models with variable kinetic functions for accurate","volume":"133","author":"Reinisch","year":"2010","journal-title":"J. Chem. Phys."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"8430","DOI":"10.1021\/jp052793n","article-title":"Uncertainties in scaling factors for ab initio vibrational frequencies","volume":"109","author":"Irikura","year":"2005","journal-title":"J. Phys. Chem. A"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"114109","DOI":"10.1063\/1.3493630","article-title":"Calibration sets and the accuracy of vibrational scaling","volume":"133","author":"Teixeira","year":"2010","journal-title":"J. Chem. Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"11683","DOI":"10.1021\/jp073974n","article-title":"An Evaluation of Harmonic Vibrational Frequency Scale Factors","volume":"111","author":"Merrick","year":"2007","journal-title":"J. Phys. Chem. A"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2872","DOI":"10.1021\/ct100326h","article-title":"Computational Thermochemistry: Scale Factor Databases and Scale Factors for Vibrational Frequencies Obtained from Electronic Model Chemistries","volume":"6","author":"Alecu","year":"2010","journal-title":"J. Chem. Theory Comput."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2339","DOI":"10.1002\/jcc.21811","article-title":"Harmonic Vibrational Frequencies: Scale Factors for Pure, Hybrid, Hybrid Meta, and Double-Hybrid Functionals in Conjunction with Correlation Consistent Basis Sets","volume":"32","author":"Laury","year":"2011","journal-title":"J. Comput. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3774","DOI":"10.1021\/acs.jctc.6b00554","article-title":"Frequency Scale Factors for Some Double-Hybrid Density Functional Theory Procedures: Accurate Thermochemical Components for High-Level Composite Protocols","volume":"12","author":"Chan","year":"2016","journal-title":"J. Chem. Theory Comput."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"014108","DOI":"10.1063\/1.1824881","article-title":"Anharmonic vibrational properties by a fully automated second-order","volume":"122","author":"Barone","year":"2005","journal-title":"J. Chem. Phys."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3059","DOI":"10.1063\/1.1637580","article-title":"Vibrational zero-point energies and thermodynamic functions beyond the harmonic approximation","volume":"120","author":"Barone","year":"2004","journal-title":"J. Chem. Phys."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1140\/epjp\/s13360-021-01338-7","article-title":"Enthalpy, Gibbs free energy and specific heat in constant pressure for diatomic molecules using improved deformed exponential-type potential (IDEP)","volume":"136","author":"Habibinejad","year":"2021","journal-title":"Eur. Phys. J. Plus"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1007\/s00894-024-05845-z","article-title":"Energy spectrum of selected diatomic molecules (H2, CO, I2, NO) by the resolution of Schrodinger equation for combined potentials via NUFA method","volume":"30","author":"Reggab","year":"2024","journal-title":"J. Mol. Model."},{"key":"ref_23","first-page":"43","article-title":"Potential energy curves and dissociation energies for some diatomic molecules by using two different functions","volume":"3","author":"Ayaash","year":"2016","journal-title":"J. Adv. Res. Appl. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"035401","DOI":"10.1088\/1402-4896\/ac514c","article-title":"Comparison study of bound states for diatomic molecules using Kratzer, Morse, and modified Morse potentials","volume":"97","author":"Sandouqa","year":"2022","journal-title":"Phys. Scr."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"075413","DOI":"10.1088\/1402-4896\/ad59db","article-title":"An innovative treatment of anharmonic and Morse potentials to determine the spectroscopic constants of diatomic molecules","volume":"99","author":"Amila","year":"2024","journal-title":"Phys. Scr."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"085401","DOI":"10.1088\/1402-4896\/ab9bdc","article-title":"A new modified Morse potential energy function for diatomic molecules","volume":"95","author":"Desai","year":"2020","journal-title":"Phys. Scr."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"100204","DOI":"10.1016\/j.rechem.2021.100204","article-title":"Accuracy of Morse and Morse-like oscillators for diatomic molecular interaction: A comparative study","volume":"3","author":"Pingak","year":"2021","journal-title":"Results Chem."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Denisov, G.S., and Denisov, I.G. (2021). More about properties of Morse oscillator. Spectrochim. Acta A Mol. Biomol. Spectrosc., 262.","DOI":"10.1016\/j.saa.2021.120111"},{"key":"ref_29","unstructured":"Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Barone, V., Petersson, G.A., and Nakatsuji, H. (2016). Gaussian 09, Revision A.02, Gaussian, Inc."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"224108","DOI":"10.1063\/5.0004608","article-title":"The ORCA quantum chemistry program package","volume":"152","author":"Neese","year":"2020","journal-title":"J. Chem. Phys."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1002\/jcc.540141112","article-title":"General Atomic and Molecular Electronic Structure System","volume":"14","author":"Schmidt","year":"1993","journal-title":"J. Comput. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"40","DOI":"10.6060\/tcct.2017604.5490","article-title":"Statthermo\u00ae\u2014New software for calculation of thermodynamic functions","volume":"60","author":"Dunaev","year":"2017","journal-title":"Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"012076","DOI":"10.1088\/1742-6596\/633\/1\/012076","article-title":"New implementation of the first-order perturbation theory for calculation of interatomic vibrational amplitudes and corrections in gas electron diffraction","volume":"633","author":"Vishnevskiy","year":"2015","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_34","unstructured":"Ignatov, S.K. (2024, November 10). Moltran v.2.5\u2014Program for Molecular Visualization and Thermodynamic Calculations. University of Nizhny Novgorod, Nizhny Novgorod, Russia. Available online: http:\/\/www.qchem.unn.ru\/moltran\/."},{"key":"ref_35","unstructured":"Johnson, R.D. (2024, November 10). NIST Standard Reference Database Number 101, Available online: http:\/\/cccbdb.nist.gov."},{"key":"ref_36","unstructured":"McQuarrie, D.A. (1976). Statistical Mechanics, Harper & Row."},{"key":"ref_37","unstructured":"McQuarrie, D.A., and Simon, J.D. (1999). Molecular Thermodynamics, University Science Books."},{"key":"ref_38","unstructured":"Ochterski, J.W. (2024, November 10). Thermochemistry in Gaussian. Available online: https:\/\/gaussian.com\/wp-content\/uploads\/dl\/thermo.pdf."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1103\/RevModPhys.80.633","article-title":"CODATA Recommended Values of the Fundamental Physical Constants: 2006","volume":"80","author":"Mohr","year":"2008","journal-title":"Rev. Mod. Phys."},{"key":"ref_40","first-page":"1","article-title":"NIST-JANAF Thermochemical Tables, Fourth Edition","volume":"9","author":"Chase","year":"1998","journal-title":"J. Phys. Chem. Ref. Data"},{"key":"ref_41","unstructured":"Linstrom, P.J., and Mallard, W.G. (2023). NIST Standard Reference Database Number 69, National Institute of Standards and Technology."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"8533","DOI":"10.1021\/jp011331g","article-title":"Chlorofluoroamines: Ab Initio and DFT Studies on Their Structure, Enthalpies of Formation, and Unimolecular Reaction Pathways","volume":"105","author":"Shamasundar","year":"2001","journal-title":"J. Phys. Chem. A"}],"container-title":["Computation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-3197\/12\/11\/229\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:32:40Z","timestamp":1760113960000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-3197\/12\/11\/229"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,11,15]]},"references-count":42,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2024,11]]}},"alternative-id":["computation12110229"],"URL":"https:\/\/doi.org\/10.3390\/computation12110229","relation":{},"ISSN":["2079-3197"],"issn-type":[{"type":"electronic","value":"2079-3197"}],"subject":[],"published":{"date-parts":[[2024,11,15]]}}}