Atomic relaxations around vacancy clusters in molybdenum and their effects on trapped-positron lifetime

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© 1988 American Physical Society (APS). This is the accepted version of the following article: Khanna, S. N. & Rao, B. K. & Jena, P. & Esterling, D. & Puska, Martti J. 1988. Atomic relaxations around vacancy clusters in molybdenum and their effects on trapped-positron lifetime. Physical Review B. Volume 37, Issue 1. 6-11. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.37.6, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.37.6.

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

1988

Major/Subject

Mcode

Degree programme

Language

en

Pages

6-11

Series

Physical Review B, Volume 37, Issue 1

Abstract

The relaxations of first- and second-nearest-neighbor shells of atoms around a monovacancy and around voids corresponding to the removal of 9, 15, 27, and 51 atoms in molybdenum have been calculated by minimizing the total energies with respect to atomic displacements. The energies are obtained by using the tight-binding scheme within the moments and continued-fraction formulation. The sign of the atomic displacements (inward or outward) of both the nearest and next-nearest neighbors varies with the size of the void. In addition, the displacements exhibit oscillations as a function of void size and do not appear to converge to atomic relaxations characteristic on surfaces even for the largest void studied. The relaxation of the first-nearest neighbor has a significant effect on the lifetime of positrons trapped in monovacancies, bringing theory to much better agreement with experiment. This effect, however, diminishes and becomes insignificant as voids grow in size.

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Keywords

atomic displacements, atomic relaxations

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Citation

Khanna, S. N. & Rao, B. K. & Jena, P. & Esterling, D. & Puska, Martti J. 1988. Atomic relaxations around vacancy clusters in molybdenum and their effects on trapped-positron lifetime. Physical Review B. Volume 37, Issue 1. 6-11. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.37.6.