Coherence-Length Effects in Fast Atom Diffraction at Grazing Incidence

被引：6

作者：

Gravielle, Maria Silvia ^{[1
]}

Miraglia, Jorge Esteban ^{[1
]}

Frisco, Leandro ^{[2
]}

机构：

[1] UBA, CONICET, IAFE, Casilla Correo 67,Sucursal 28,C1428EGA, Buenos Aires, DF, Argentina

[2] Univ Buenos Aires, FCEN, Dept Fis, C1428EGA, Buenos Aires, DF, Argentina

来源：

ATOMS | 2018年 / 6卷 / 04期

关键词：

coherence-length; atom-surface collision; focusing;

D O I：

10.3390/atoms6040064

中图分类号：

O64 [物理化学（理论化学）、化学物理学]; O56 [分子物理学、原子物理学];

学科分类号：

070203 ; 070304 ; 081704 ; 1406 ;

摘要：

Coherence properties of projectiles, found relevant in ion-atom collisions, are investigated by analyzing the influence of the degree of coherence of the atomic beam on interference patterns produced by grazing-incidence fast-atom diffraction (GIFAD or FAD). The transverse coherence length of the projectiles, which depends on the incidence conditions and the collimating setup, determines the overall characteristics of GIFAD distributions. We show that for atoms scattered from a LiF(001) surface after a given collimation, we can modify the interference signatures of the angular spectra by varying the total impact energy, while keeping the normal energy as a constant. Also, the role played by the geometry of the collimating aperture is analyzed, comparing results for square and circular openings. Furthermore, we study the spot-beam effect, which is due to different focus points of the impinging particles. We show that when a region narrower than a single crystallographic channel is coherently illuminated by the atomic beam, the spot-beam contribution strongly affects the visibility of the interference structures, contributing to the gradual quantum-classical transition of the projectile distributions.

引用

页数：16

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