A theoretical study of the effects of an external electric field on adsorbate-surface systems

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dc.contributor.advisorNordlander, Peter J.en_US
dc.creatorAkpati, Hilary Chukwumaen_US
dc.date.accessioned2009-06-04T08:17:24Zen_US
dc.date.available2009-06-04T08:17:24Zen_US
dc.date.issued1997en_US
dc.description.abstractWe have used the density functional ab initio method to conduct investigations on the effects of an applied electric field on the chemisorption bonds of adsorbate-surface systems, and on the reactivity of a gas phase semiconductor cluster. In STM current-induced excitation of adsorbates, lateral energy transfer among adsorbates tend to delocalize the excitation, and reduce resolution. We show that the strength of chemical bonds can be increased or decreased depending on the strength and direction of the applied electric field. By shifting the excitation energy of an adsorbate below the tip, energy transfer away from the site can be inhibited, and thereby lead to adsorbate excitation localization. The details of the field-induced shifts of an adsorbate-surface bonding features are shown to depend on their dipolar polarization. In the case of the reactivity of GaAs clusters with ammonia, recent experiments indicate that NH$\sb3$ adsorption rate depends strongly on cluster size, Ga/As composition ratio, and cluster charge state. We characterize the reactivity of NH$\sb3$ at various sites of a $\rm Ga\sb5As\sb5$ cluster in terms of the adsorbate binding energy and charge transfer, showing a strong correlation between the two. The dependence of the cluster reactivity on its charge state is deduced.en_US
dc.format.extent75 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoTHESIS PHYS. 1997 AKPATIen_US
dc.identifier.citationAkpati, Hilary Chukwuma. "A theoretical study of the effects of an external electric field on adsorbate-surface systems." (1997) Diss., Rice University. <a href="https://hdl.handle.net/1911/19126">https://hdl.handle.net/1911/19126</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/19126en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectMolecular physicsen_US
dc.subjectCondensed matter physicsen_US
dc.titleA theoretical study of the effects of an external electric field on adsorbate-surface systemsen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentPhysicsen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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