NIST-JANAF thermochemical tables.: II.: Three molecules related to atmospheric chemistry:: HNO3, H2SO4, and H2O2

The structural, spectroscopic, and thermochemical properties of three polyatomic molecules with internal rotation-HNO3(g), H2SO4(g), and H2O2(g)-have been reviewed. Three revised ideal gas thermodynamic tables result from this critical examination. The revisions involved the consideration of new spectroscopic information and the use of theoretical results to model the internal rotation in the H2SO4 molecule. Compared to previous calculations, the entropies at 298.15 K are unchanged for HNO3 and H2O2, but the high temperature values (T > 4000 K) are significantly different. As for H2SO4, its thermodynamic functions differ significantly from values calculated earlier. (C) 2003 American Institute of Physics.