Perfect gas thermodynamic properties of methanal, ethanal and their deuterated species

Abstract

Employing recent and reliable selected molecular, spectroscopic, and thermal constants, the perfect gas thermodynamic properties [ H 0  H 0 0, ( G 0  H 0 0)/ T, S 0, C 0 p, Δ H 0 f, and Δ G 0 f], for methanal (formaldehyde), methanal- d 1, methanal- d 2, ethanal (acetaldehyde), ethanal- d 1, and ethanal- d 4 were evaluated over the temperature range from 0 to 1500 K and 1 atm by statistical mechanical methods using rigid-rotor and harmonic-oscillator approximations. The internal rotation contributions of -CH 3 and -CD 3 rotors to the thermodynamic properties were computed based on internal rotation partition functions formed by summation of calculated internal rotation energy levels. The results compare well with available experimental data.