Microtopography of the barite (001) face during growth: AFM observations and PBC theory

Under moderate supersaturation conditions, crystal growth on the barite (0 0 1) surface takes place by the development of two-dimensional nucleation simultaneously with the advancement of molecular-height cleavage steps on the surface. The most frequent growth steps have a height of a half-unit cell...

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Detalles Bibliográficos
Autores: Pina Martínez, Carlos Manuel, Bosbach, Dirk, Prieto Rubio, Manuel, Putnis, Andrew
Tipo de recurso: artículo
Fecha de publicación:1998
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/57124
Acceso en línea:https://hdl.handle.net/20.500.14352/57124
Access Level:acceso abierto
Palabra clave:548.5
Microtopography
Crystal Growth
Barite
Cristalografía (Geología)
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spelling Microtopography of the barite (001) face during growth: AFM observations and PBC theoryPina Martínez, Carlos ManuelBosbach, DirkPrieto Rubio, ManuelPutnis, Andrew548.5MicrotopographyCrystal GrowthBariteCristalografía (Geología)Under moderate supersaturation conditions, crystal growth on the barite (0 0 1) surface takes place by the development of two-dimensional nucleation simultaneously with the advancement of molecular-height cleavage steps on the surface. The most frequent growth steps have a height of a half-unit cell, as has been predicted by periodic bond chain (PBC) theory, and they are parallel to the S1 2 0T PBC directions. Along opposite directions the velocity of S1 2 0T growth steps is strongly anisotropic. Moreover, the directions of fast growth alternate for successive elementary growth layers. The anisotropy of the growth rates can be explained by taking into account the crystallographic features and orientation of the complete PBC within each (0 0 2) elementary growth slice. On the other hand, the alternation of the fast growth direction for S1 2 0T steps in successive d002 growth layers is related to the existence of a 21 screw axis perpendicular to the (0 0 1) surface. Two-dimensional nucleation on the barite (0 0 1) surface is characterized by the development of islands with a circular sector shape and half-unit cell in height. The two-dimensional islands nucleated on the initial surface show the same orientation. As growth proceeds, islands coalesce and a homogeneous layer with a thickness of 3.5 A is formed. Nucleation on this new surface produces islands oriented in the opposite sense to those in the previous layer. Goniometric measurements and X-ray di¤raction experiments conÞrm that the straight edges of the islands are parallel to the [1 2 0] and [1 2 0] crystallographically equivalent directions. The third side of each island is curved, rough and tangent to [010]. Both the morphology and development of two-dimensional nuclei on the barite (001) face clearly indicate that the growth process is structurally controlled. The asymmetry of [120], [120] and [010] PBCs and their crystallographic features can be considered as responsible for the geometry and spread of the circular sector islands formed on each elementary (002) growth layer.Elsevier Science B.V.Universidad Complutense de Madrid19981998-01-0119981998-01-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/57124reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/571242026-06-02T12:44:21Z
dc.title.none.fl_str_mv Microtopography of the barite (001) face during growth: AFM observations and PBC theory
title Microtopography of the barite (001) face during growth: AFM observations and PBC theory
spellingShingle Microtopography of the barite (001) face during growth: AFM observations and PBC theory
Pina Martínez, Carlos Manuel
548.5
Microtopography
Crystal Growth
Barite
Cristalografía (Geología)
title_short Microtopography of the barite (001) face during growth: AFM observations and PBC theory
title_full Microtopography of the barite (001) face during growth: AFM observations and PBC theory
title_fullStr Microtopography of the barite (001) face during growth: AFM observations and PBC theory
title_full_unstemmed Microtopography of the barite (001) face during growth: AFM observations and PBC theory
title_sort Microtopography of the barite (001) face during growth: AFM observations and PBC theory
dc.creator.none.fl_str_mv Pina Martínez, Carlos Manuel
Bosbach, Dirk
Prieto Rubio, Manuel
Putnis, Andrew
author Pina Martínez, Carlos Manuel
author_facet Pina Martínez, Carlos Manuel
Bosbach, Dirk
Prieto Rubio, Manuel
Putnis, Andrew
author_role author
author2 Bosbach, Dirk
Prieto Rubio, Manuel
Putnis, Andrew
author2_role author
author
author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 548.5
Microtopography
Crystal Growth
Barite
Cristalografía (Geología)
topic 548.5
Microtopography
Crystal Growth
Barite
Cristalografía (Geología)
description Under moderate supersaturation conditions, crystal growth on the barite (0 0 1) surface takes place by the development of two-dimensional nucleation simultaneously with the advancement of molecular-height cleavage steps on the surface. The most frequent growth steps have a height of a half-unit cell, as has been predicted by periodic bond chain (PBC) theory, and they are parallel to the S1 2 0T PBC directions. Along opposite directions the velocity of S1 2 0T growth steps is strongly anisotropic. Moreover, the directions of fast growth alternate for successive elementary growth layers. The anisotropy of the growth rates can be explained by taking into account the crystallographic features and orientation of the complete PBC within each (0 0 2) elementary growth slice. On the other hand, the alternation of the fast growth direction for S1 2 0T steps in successive d002 growth layers is related to the existence of a 21 screw axis perpendicular to the (0 0 1) surface. Two-dimensional nucleation on the barite (0 0 1) surface is characterized by the development of islands with a circular sector shape and half-unit cell in height. The two-dimensional islands nucleated on the initial surface show the same orientation. As growth proceeds, islands coalesce and a homogeneous layer with a thickness of 3.5 A is formed. Nucleation on this new surface produces islands oriented in the opposite sense to those in the previous layer. Goniometric measurements and X-ray di¤raction experiments conÞrm that the straight edges of the islands are parallel to the [1 2 0] and [1 2 0] crystallographically equivalent directions. The third side of each island is curved, rough and tangent to [010]. Both the morphology and development of two-dimensional nuclei on the barite (001) face clearly indicate that the growth process is structurally controlled. The asymmetry of [120], [120] and [010] PBCs and their crystallographic features can be considered as responsible for the geometry and spread of the circular sector islands formed on each elementary (002) growth layer.
publishDate 1998
dc.date.none.fl_str_mv 1998
1998-01-01
1998
1998-01-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/57124
url https://hdl.handle.net/20.500.14352/57124
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier Science B.V.
publisher.none.fl_str_mv Elsevier Science B.V.
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.300724

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