Observation of rotationally mediated focused inelastic resonances in D{sub 2} scattering from Cu(001)
- Max-Planck Institut fuer Stroemungsforschung, Bunsenstrasse 10, D-37073 Goettingen (Germany)
- Istituto Nazionale di Fisica della Materia, Dipartimento di Fisica dell Universita, Via Celoria 16, 20133 Milano (Italy)
Rotationally mediated focused inelastic resonances (RMFIR{close_quote}s) in the angular distributions of D{sub 2} scattered from Cu(001) are observed. The FIR effect involves a phonon-assisted focusing of an incident beam of arbitrary energy and direction into a final channel of one single well-defined energy and direction. Surprisingly for an incident energy E{sub i}=27meV the RMFIR conditions for the scattered beam coincide with the kinematic conditions required for a further elastic selective adsorption mechanism called the rotationally mediated critical kinematic (RMCK) effect. By taking advantage of the RMFIR and elastic RMCK effects, three effective bound states of energy {epsilon}{sub n,J}={minus}21.5meV, {minus}12.4meV, and {minus}10.3meV are determined. They are attributed to the lowest bound states {epsilon}{sub 0}={minus}28.9meV and {epsilon}{sub 1}={minus}19.8meV combined with the rotational excitation energy for J=1 to be B{sub rot}J(J+1)=7.41meV, respectively, and {epsilon}{sub 3}={minus}10.3meV combined with the rotational ground state (J=0). While the {epsilon}{sub 1} and {epsilon}{sub 3} states appear as maxima in the angular distribution at RMFIR conditions, the {epsilon}{sub 0} yields a striking minimum which represents the first evidence of what we call an anti-FIR feature. Theoretical arguments to explain the different FIR signatures observed are provided. A fit of a phenomenological interaction potential to the experimental bound-state values yields a value for the well depth D=32.5meV which is somewhat deeper than that found previously. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 543821
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 15; Other Information: PBD: Oct 1997
- Country of Publication:
- United States
- Language:
- English
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