STUDIES OF DESORPTION AND SURFACE DIFFUSION BY PULSED LASER TECHNIQUES.

D. Burgess*, I. Hussla, Peter Stair, R. Viswanathan, Eric Weitz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Temperature programmed desorption (TPD) has been used extensively to investigate molecule-surface interactions. Recently, pulsed-laser-induced thermal desorption has been used to develop techniques for investigating molecular desorption dynamics and molecular surface diffusion. An understanding of pulsed-laser-induced thermal desorption is best obtained with reference to ordinary thermal desorption spectroscopy. In the reported study, the surface diffusion of CO on copper was studied by observing the time dependence for the recovery of the desorption flux from a small area on the Cu(100) surface following the depletion of the adsorbed CO in that area by a series of laser pulses. Measured diffusion coefficients range from 2 multiplied by 10** minus **7 cm**2sec** minus **1 at 110 K to 3. 5 multiplied by 10** minus **6 cm**2sec** minus **1 at 140 K. The approximate activation energy for diffusion derived from these measurements is 12 kJ/mole. An investigation of the desorption and decomposition of formaldehyde on clean and oxidized copper surfaces using pulsed-laser-induced thermal desorption is currently in progress. These experiments are designed to determine whether the thermal chemistry observed with ordinary thermal desorption can be altered using the very fast heating and cooling possible with the pulsed laser technique. Results of these experiments are discussed.

Original languageEnglish (US)
Number of pages1
JournalAmerican Chemical Society, Division of Petroleum Chemistry, Preprints
Volume29
Issue number3
StatePublished - Aug 1 1984

ASJC Scopus subject areas

  • Fuel Technology

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