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Optically Driven Vapor Transport Of Solids

IP.com Disclosure Number: IPCOM000097325D
Original Publication Date: 1962-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Jona, F: AUTHOR [+2]

Abstract

Solids can be transported through the vapor phase by means of a reaction with a reactive gas in the presence of a temperature gradient. The driving energy for such a process can also be supplied by sources other than thermal, i. e., by sources other than a temperature gradient. This transport is an optically driven system.

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Optically Driven Vapor Transport Of Solids

Solids can be transported through the vapor phase by means of a reaction with a reactive gas in the presence of a temperature gradient. The driving energy for such a process can also be supplied by sources other than thermal, i.
e., by sources other than a temperature gradient. This transport is an optically driven system.

A tube containing ZnS at one end and an atmosphere of I(2) gas, is allowed to come to equilibrium at constant temperature. The equilibrium is: ZnS((s)) + I(2)((g)) = ZnI(2)((g)) + 1/2 S(2)((g)) Provided the temperature is sufficiently high, no transport occurs.

Now, let ultraviolet light shine upon one end of the tube (near the charge) such that some of the I(2) is dissociated, i.e., I(2)((g)) /h/ =2I(g) and

ZnS((s)) + 2I((g)) = ZnI(2)((g)) + 1/2 S(2)((g)) Equilibrium
(3) represents a reaction moving to the right since I. is more reactive than I(2) at temperatures below 1400 degrees K. This results in an excess pressure of ZnI(2) and S(2)((g)) in the neighborhood of the charge producing a diffusion of these compounds to other parts of the system. Equilibrium (1) will operate and cause deposition of solid in these other regions resulting in a net transport of solid.

Other types of energy can also be supplied to Equilibrium (2), e.g., electrical energy. Thus, electrically driven vapor transport of solids is obtainable.

Although the process is described as involving the specific material, ZnS, the general...