Theoretical Study of the Geometry and Spectrum of Nitrous Oxide

Abstract

A series of ab initio SCF MO calculations is carried out for the nitrous oxide molecule as a function of internuclear angle in both NNO and NON arrangements. Investigation of the results of these calculations indicates that this molecule favors the nonsymmetric NNO arrangement mainly as a result of the net stabilization its occupied π MO's derive from having the more electronegative oxygen atom at the terminal position of the system. Generalization of this point leads to a qualitative explanation for the almost universal preference of triatomic molecules for equilibrium structures in which the most electropositive atom of the three lies at the middle position of the system. The calculations are also employed to discuss the applicability of general rules governing questions regarding the geometry of symmetric triatomic molecules to analogous problems concerning the nonsymmetric members of this family. Finally, a large-scale CI calculation for the linear equilibrium geometry of NNO is carried out in order to obtain a detailed list of assignments for the absorption lines in the electronic spectrum of this molecule.