J. Phys. Chem. 1982,
86,2345-2349
2345
Ab Initio Self-Consistent Field Calculations of NO,-( H,O), and NOJ H,O), Clusters J. M. Howell,+ A. M. Sapse,' E. Singman,' and G. Synderg Chemistry !Jepartment, City University of New York, Brook!m College, Brooklyn, New York 112 IO; The Graduate Center and John Jay College, New York City, New York 10019;and Pueensborough Communlty Co//ege, Bayside, New York 11364 (Received: September 2, 198 1; I n Final Form: January 12, 1982)
Ab initio self-consistent field calculations are performed on N02-(H20),and NO;(H20), (n = 1-3) clusters. Optimized geometries, total energies, binding energies, and net atomic charges are presented for various structures of the clusters.
Introduction Observations of negative ions in the atmosphere have stimulated many studies of the association reactions of negative ions with such molecules as water, SO2, and others. Such studies can result in a better understanding of the nucleation phenomena, particularly as related to the species existing in the atmosphere. Numerous negative ions have been experimentally observed in the atmosphere such as O ;, NO;, and CO;. Their properties are greatly influenced by the extent to which they are hydrated. In particular, the kinetic processes may depend on the number of water molecules attached to an ion. Since the degree of hydration may alter the rate of conversion from one species to another, the negative-ion composition of the atmosphere may be changed-l The electron density of the atmosphere and as such its electrical conductivity are controlled by the negative ions. Electrons are exchanged between neutral species and negative ions through such processes as photodetachment or associative detachment reactions. By stabilizing negative ions against electron detachment, hydration can affect conductivity. Since electron density is much smaller at lower altitudes, the hydration can prove to be an even more important factor by preventing ion-ion recombination and increasing the ion stability. The process of stabilization of the electron on the negative ion due to hydration2s3may affect the altitude at which electron density becomes larger than the negativeion density, therefore influencing the radio wave propagation in the D region of the atmosphere. In this study, we focusd our attention on the NO< and NO2- ions hydrates. Experimental evidence1v2points to the existence of NO
