Theoretical studies of water on substrates

<p>"Model interaction potentials for H₂O on a basal f)-silver iodide substrate containing two types of defects, a potassium impurity and a four atomic layer ledge, are used to calculate optimal binding energy contours for the adsorbed H₂O molecule. (J. Phys. Chern. 84, 1473(1980)). The model substrate with the potassium impurity appears to increase the optimal binding energy at the preferred adsorption sites to 23 kcal/rnol -- a value approximately 40 % larger than the maximal binding energy sites on the defect-free model silver-exposed basal plane of AgI. The impurity also distorts the hexagonal symmetry of the pref erred adsorption sites, drawing them towards the impurity. The four-layer ledge produces sites parallel to the ledge with optimal binding energy equal to 23 kcal/rnol compared to 20 (16) kcal/mol for maximal binding energy sites on the prism (iodine-exposed basal) face of the defect-free model AgI substrate. In a second study a formalism is presented for estimating the critical cluster size,n , and steady state nucleation rate, J, for adsorbed monolayer formation. The latter is combined with a Metropolis Monte Carlo technique and applied to water clusters on a featureless Lennard-Jones substrate with average H₂O substrate binding energy and short-range forces parameters comparable to the model iodine-exposed basal AgI substrate. At 2 65 °K, the values 1< n* < 2 and, J ~ 10²⁴cm^-2 sec^-l are predicted at water saturation. A comparison with results for water adsorbed on the model iodine-exposed basal AgI substrate (J. Chem. Phys. 78, 420(1983)) indicates that on both substrates a water mono layer forms rapidly and with approximately the same nucleation rate. The present results give an order of magnitude larger value of J for the smooth substrate and hence imply that the latter forms a monolayer at lower vapor pressures than the model AgI'--Abstract, p. ii</p>

Name thesis:degree_name

Ph. D. in Physics

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Terrazas, Sergio M.

• Physics

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/1034

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-2036