The energy of N sub 2 H sub 2 and related compounds

Journal Article · Sun Sep 15 00:00:00 EDT 1991 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.461762· OSTI ID:5312783

Pople, J A ^[1]; Curtiss, L A ^[2]

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1. Department of Chemistry, Carnegie-Mellon University, Pittsburgh, Pennsylvania (USA)
2. Chemical Technology and Materials Science Divisions, Argonne National Laboratory, Argonne, Illinois (USA)

{ital Ab} {ital initio} molecular orbital theory at the G2 level has been used to study the energy of N{sub 2}H{sub 2} and related compounds. Overall, the agreement between theory and experiment is good. The G2 enthalpy of formation {Delta}{ital H}{sup 0}{sub {ital f}0}(N{sub 2}H{sub 2}) of 49.6 kcal/mol supports the experimental estimate of {ge}46.6 kcal/mol derived by Ruscic and Berkowitz (J. Chem. Phys. {bold 95}, xxx4 (1991)) in a recent photoionization study. Predicted dissociation energies are {ital D}{sub 0}(HN NH)=122.8 kcal/mol, {ital D}{sub 0}(HNNH--H)=43.6 kcal/mol, and {ital D}{sub 0}(H{sub 2}N NH--H)=82.1 kcal/mol. The G2 value for the proton affinity (PA) of N{sub 2} at 298 K is PA{sub 298}=118.1 kcal/mol. The G2 ionization potential of N{sub 2}H{sub 3} of 7.54 eV is in agreement with the new value of {le}7.61 eV reported by Ruscic and Berkowitz. The G2 results for the ionization potential of N{sub 2}H{sub 4} and the appearance potential of N{sup +}{sub 2} from N{sub 2}H{sub 2} are in disagreement with experimental results suggesting that detection of the origins in these cases are thwarted by large geometry changes and significant Franck--Condon effects.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5312783
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 95:6; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
CHEMICAL BONDS
DISSOCIATION ENERGY
ENERGY
ENTHALPY
FORMATION HEAT
HYDRIDES
HYDROGEN COMPOUNDS
IONIZATION POTENTIAL
MOLECULAR ORBITAL METHOD
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
PHYSICAL PROPERTIES
REACTION HEAT
THERMODYNAMIC PROPERTIES