Consideration of the kinetics of the evaporation of peptides leads to two approaches to volatility enhancement. An obvious direction to take is to attempt to reduce the energy of bonding of molecules to surfaces by dispersal onto surfaces which are relatively inert.

The isotopi~ composition of the products of the controlled thermal decomposition of ammonium nitrate has been s~udle~. It has been found that small amounts of water are necessary to initiate the decomposition of ammomum mtrate. NlliH4NOa has been found to yield exclusively the isomer NlliN 14 0. Some inferences are drawn from this observation regarding the mechanism of the reaction.Oxygen and nitrogen isotope effects accompanying the decomposition have been studied with material of "natural" isotopic composition. Satisfactory agreement is found between the experimental results and theoretical calculations.A method for the isotopic analysis of nitrates for 0 18 is outlined.

Deuteron-deuteron fusion, detected via the 3-MeV protons produced, is shown to occur when singly charged clusters of 25 to 1300 D2O molecules, accelerated to 200 to 325 keV, impinge on TiD targets. The energy and cluster-size dependence of the fusion rate are discussed. The fusion events are shown to originate from the cluster-ion impacts rather than from D + or D2O 4 " ions in the beam. The observed rates may be correlated with the compressions and high energy densities created in collision spikes by cluster-ion impacts. PACS numbers: 79.20.Rf, 25.45.-z, 47.40.Nm, 52.50.Lp

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