Abstract
This paper reports an efficient closed-form representation of the heat capacity of linear triatomic molecules. An approximate method is proposed for factorizing the vibrational and rotational contributions to the ro-vibrational partition function using average vibrational quantum numbers. Single-valued analytical representations of the vibrational and rotational partition functions are also derived. The reliability of the proposed method for calculating heat capacity is verified by comparison with experimental data and theoretical calculations using the direct summation method with exact values of energy levels. The new approach is much more efficient than the explicit sum-over-states method.
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X.-Q. Song, C.-W. Wang, C.-S. Jia, Thermodynamic properties for the sodium dimer. Chem. Phys. Lett. 673, 50 (2017). https://doi.org/10.1016/j.cplett.2017.02.010
C.-J. Jia, L.-H. Zhang, C.-W. Wang, Thermodynamic properties for the lithium dimer. Chem. Phys. Lett. 667, 211 (2017). https://doi.org/10.1016/j.cplett.2016.11.059
B. Tang, Y.-T. Wang, X.-L. Peng, L.-H. Zhang, C.-J. Jia, Efficient predictions of Gibbs free energy for the gases CO, BF, and gaseous BBr. J. Mol. Struct. 1199, 126958 (2020). https://doi.org/10.1016/j.molstruc.2019.126958
H. Louis, B.I. Ita, N.I. Nzeata, Approximate solution of the Schrödinger equation with Manning-Rosen plus Hellmann potential and its thermodynamic properties using the proper quantization rule. Eur. Phys. J. Plus 134, 315 (2019). https://doi.org/10.1140/epjp/i2019-12835-3
A. Diaf, M. Hachama, M.M. Ezzine, Thermodynamic properties for some diatomic molecules with the q-deformed hyperbolic barrier potential. Mol. Phys. 121, e2198045 (2023). https://doi.org/10.1080/00268976.2023.2198045
C.A. Onate, M.C. Onyeaju, U.S. Okorie, A.N. Ikot, Thermodynamic functions for boron nitride with q-deformed exponential type potential. Results Phys. 16, 102959 (2020). https://doi.org/10.1016/j.rinp.2020.102959
G.-H. Liu, Q.-C. Ding, C.-W. Wang, C.-S. Jia, Unified non-fitting explicit formulation of thermodynamic properties for five compounds. J. Mol. Struct. 1294, 136543 (2023). https://doi.org/10.1016/j.molstruc.2023.136543
G.-H. Liu, Q.-C. Ding, C.-W. Wang, C.-S. Jia, Unified explicit formulations of thermodynamic properties for the gas NO2, and gaseous BF2 and AlCl2 radicals. Chem. Phys. Lett. 830, 140788 (2023). https://doi.org/10.1016/j.cplett.2023.140788
C.-W. Wang, J. Wang, Y.-S. Liu, J. Li, X.-L. Peng, C.-S. Jia, L.-H. Zhang, L.-Z. Yi, J.-Y. Liu, C.-J. Li, X. Jia, Prediction of the ideal-gas thermodynamic properties for water. J. Mol. Liquids 321, 114912 (2021). https://doi.org/10.1016/j.molliq.2020.114912
Q. Dong, H.I. GarsíaHernández, G.-H. Sun, M. Toutounji, S.-H. Dong, Exact solutions of the harmonic oscillator plus non-polynomial interaction. Proc. R. Soc. A 476, 20200050 (2020). https://doi.org/10.1098/rspa.2020.0050
M.L. Strekalov, On the partition function of Morse oscillators. Chem. Phys. Lett. 393, 192 (2004). https://doi.org/10.1016/j.cplett.2004.06.028
M.L. Strekalov, An accurate closed-form expression for the rovibrational partition function of diatomic molecules. Chem. Phys. Lett. 764, 138262 (2021). https://doi.org/10.1016/j.cplett.2020.138262
M.L. Strekalov, Rigorous factorization method of the vibrational and rotational contributions to the ro-vibrational partition function. Comput. Theor. Chem. 1202, 113337 (2021). https://doi.org/10.1016/j.comptc.2021.113337
P.S. Dardy, J.S. Dahler, Equilibrium constants for the formation of van der Waals dimers: calculations for Ar-Ar and Mg-Mg. J. Chem. Phys. 93, 3562 (1990). https://doi.org/10.1063/1.458788
F.V. Prudente, A. Riganelli, A.J.C. Varandas, Calculation of the rovibrational partition function using classical methods with quantum corrections. J. Phys. Chem. A 105, 5272 (2001). https://doi.org/10.1021/jp0043928
L.V. Gurvich, I.V. Veyts, C.B. Alcock, Thermodynamic Properties of Individual Substances, vol. 1, 4th edn. (Hemisphere, New York, 1991)
Y. Babou, Ph. Rivière, M.-Y. Perrin, A. Soufiani, High-temperature and nonequilibrium partition function and thermodynamic data of diatomic molecules. Int. J. Thermophys. 30, 416 (2009). https://doi.org/10.1007/s10765-007-0288-6
A.W. Irwin, Refined diatomic partition functions. I. Calculational methods and H2 and CO results. Astron. Astrophys. 182, 348 (1987)
Z. Qin, J.-M. Zhao, L.-H. Liu, High-temperature partition functions, specific heats and spectral radiative properties of diatomic molecules with an improved calculation of energy levels. JQSRT 210, 1 (2018). https://doi.org/10.1016/j.jqsrt.2018.02.004
C.-S. Jia, C.-W. Wang, L.-H. Zhang, X.-L. Peng, R. Zeng, X.-T. You, Partition function of improved Tietz oscillators. Chem. Phys. Lett. 676, 150 (2017). https://doi.org/10.1016/j.cplett.2017.03.068
C.O. Edet, U.S. Okorie, G. Osobonye, A.N. Ikot, G.J. Rampho, R. Sever, Thermal properties of Deng–Fan–Eckart potential model using Poisson summation approach. J. Math. Chem. 58, 989 (2020). https://doi.org/10.1007/s10910-020-01107-4
M.L. Strekalov, An accurate closed-form expression for the partition function of Morse oscillators. Chem. Phys. Lett. 439, 209 (2007). https://doi.org/10.1016/j.cplett.2007.03.052
G.T. Osobonye, M. Adekanmbi, A.N. Ikot, U.S. Okorie, G.J. Rampho, Thermal properties of anharmonic Eckart potential model using Euler–MacLaurin formula. Pranama-J. Phys. 95, 98 (2021). https://doi.org/10.1007/s12043-021-02122-z
H.J. Korsch, A new semiclassical expansion of the thermodynamic partition function. J. Phys. A 12, 1521 (1979). https://doi.org/10.1088/0305-4470/12/9/019
A.J. Thakkar, A technique for increasing the utility of the wigner-kirkwood expansion for the second virial coefficient. Mol. Phys. 36, 887 (1978). https://doi.org/10.1080/00268977800102011
H.H. Nielson, The vibration-rotation energies of molecules. Rev. Mod. Phys. 23, 90 (1951). https://doi.org/10.1103/RevModPhys.23.90
R.H. Tipping, J.F. Ogilvie, The influence of the potential function on vibration-rotation wave functions and matrix elements of diatomic molecules. J. Mol. Struct. 35, 1 (1976). https://doi.org/10.1016/0022-2860(76)80100-7
J. Goodsman, Diatomic Interaction Potential Theory (Academic Press, New York, 1973)
K.B. Wolf, Integral Transforms in Science and Engineering (Plenum Press, New York, 1979)
R.S. McDowell, Rotational partition functions for linear molecules. J. Chem. Phys. 88, 356 (1988). https://doi.org/10.1063/1.454608
J.E. Kilpatrick, R. Kayser, Direct partition function of the rigid diatomic rotor. J. Chem. Phys. 63, 5216 (1975). https://doi.org/10.1063/1.431305
V.M. Osipov, Partition sums and dissociation energy for 12C16O2 at high temperatures. Mol. Phys. 102, 1785 (2004). https://doi.org/10.1080/00268970412331287016
NIST Chemistry WebBook, NIST Standard Reference Database Number 69. https://doi.org/10.18434/T4D303
M. Buchowiecki, Vibrational partition function for the multi-temperature theories of high-temperature flows of gases and plasmas. J. Phys. Chem. A 124, 4048 (2020). https://doi.org/10.1021/acs.jpca.0c01161
P. Sarkar, N. Poulin, T. Carrington, Calculating rovibrational energy levels of a triatomic molecule with a simple Lanczos method. J. Chem. Phys. 110, 10269 (1999). https://doi.org/10.1063/1.478960
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Strekalov, M.L. The Heat Capacity of Triatomic Gases: An Analytical Approach. Int J Thermophys 45, 25 (2024). https://doi.org/10.1007/s10765-023-03315-x
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DOI: https://doi.org/10.1007/s10765-023-03315-x