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Science 11 April 1975:
Vol. 188. no. 4184, pp. 145 - 147
DOI: 10.1126/science.188.4184.145
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Articles

Vaporization of Solids: Evidence for a Zipper Mechanism in the Retarded Vaporization of Arsenic

Carl A. Hultman 1 and Gerd M. Rosenblatt 1

1 Department of Chemistry, Pennsylvania State University, University Park 16802

Recent observations indicate that the rate of evaporation of elemental arsenic into a vacuum is determined by the rate of formation, at screw dislocations, of kinks in ledges of molecular height. Once formed, a kink advances along the ledge, which makes a continuous spiral ramp outward from the dislocation, until the ledge terminates. A kink advances by releasing As4 molecules from the ledge. A given kink releases almost 106 As4 molecules before the next kink is initiated.

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Science. ISSN 0036-8075 (print), 1095-9203 (online)