Positive ion low-temperature fast atom bombardment mass spectra of the froz
en nitric acid-water system with an initial components ratio which provides
preferential formation of the crystalline hydrate of the nitric acid trihy
drate, HNO3. 3H(2)O, are reported, A complicated spectral pattern is create
d by a number of cluster sets which, on the basis of discussion, were attri
buted to (H2O)(n). NO+ (n = 1-3), (H2O)(n). NO2+ (n = 1, 2, (HNO3)(m). (H2O
)(n). H+ (m = 1-5 and n variable) and (H2O)(n). H+ (n = 1-9), Similarities
between the size-dependent behavior of hydrate clusters of nitrogen oxides
and nitric acid obtained with sputtering from the solid in the present low-
temperature experiments and under gas-phase conditions (reported earlier in
the literature) were revealed. A suggestion as to possibility of the yield
of the cluster ions sputtered due to energetic particle collision with the
frozen grains of water ice and nitric acid trihydrate, present in the atmo
sphere, to the total ionic population of the atmosphere is discussed. Copyr
ight (C) 1999 John Wiley & Sons, Ltd.