Grant 'Theoretical Studies of Time-of-Flight and Atom and Molecular Surface Collision'

Abstract

The finished work, dealing with cross sections for scattering from defects on surfaces, will be a classic work, since the definition of the cross section had not been done properly before. The second project has to do with trapping and sticking coefficients in low and medium energy collisions of atoms and molecules with surfaces. The aim is to lay to rest the long standing debate regarding the low energy asymptotic limit of sticking coefficients: is it 0? or 1? A student was looking at improvements to the wavepacket code for atom surface collisions. He also had started a project involving atom scattering with a vibrating adatom on a surface. Another unfinished project is inspired by some data that Tom Engel has generated on scattering of helium from stepped surfaces. He sees, at certain angles aimed into the steps, a scattering in non-Bragg directions, even though there is supposedly little or not disorder. The scattering is at half the momentum transfer of the perfect surface and rather broad, suggesting that perhaps steps of twice the usual length are involved. (JHD)

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Document Details

Document Type
Technical Report
Publication Date
Apr 04, 1990
Accession Number
ADA221705

Entities

People

  • E. J. Heller

Organizations

  • University of Washington

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Adsorbates
  • Bragg Scattering
  • Coefficients
  • Collisions
  • Diseases And Disorders
  • Low Temperature
  • Molecules
  • Momentum
  • Momentum Transfer
  • Scattering
  • Students

Fields of Study

  • Physics

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Military History of the United States in the 20th Century.
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.