6805

6347

كارشناسي ارشد

ماده چگال

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1390

[هشت]،95ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

جواد هاشمي فر

هادي اكبرزاده

12/4/91

مهدي رنجبر

مجتبي اعلايي

فيزيك

ID6347

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

First Principles Study of Structural Electronic Magnetic and Vibrational Properties of Copper Nanocluster and Its Alloys With Palladium By Using Full Potential Software FHI aims Hamideh Kahnouji h kahnouji@ph iut ac ir 2 7 2012 Department of Physics Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language PersianSupervisor Dr S J Hashemifar hashemifar@cc iut ac irAbstractOf the most prominent properties of Nanoparticles is the high ratio of surface to volume which causesthe domination of the surface properties and results in novel properties comparing with the correspond ing bulk material One of the consequences of surface properties is the enhancement in the chemicalactivity of the system that may improve the efficiency of the chemical catalyses in an effective manner Copper nanoparticles have various applications in catalyses and industries therefore in this thesis theproperties of pure and alloyed copper nanoclusters are studied via ab initio calculations by using thecomputational packet of Frite Habber Institue ab initio molecular simulation FHI aims This allelectron and full potential calculation packet is used to explain the molecules and materials propertiesefficiently and precisely In the software FHI aims one may obtain almost the precise position of theHighest Occupied Molecular Orbital HOMO and Lowest Unoccupied Molecular Orbital LUMO and consequently the electronic properties of the system via implying the many body GW correc tion At first in order to verify validity of the FHI aims calculations Copper dimer were calculatedby using FHI aims and Wien2k packets The correspondence of the two sets of results ensured usin continuing the calculation by the FHI aims software Then the input parameter optimization andchoosing the proper exchange correlation functional were performed and the structural magnetic vi brational and electronic properties of the pure nanoclusters of copper including dimer through nineatomic clusters were studied A structural transition from two dimension to three dimension was ob served between the six and seven atomic nanoclusters and accordingly a peak is seen in the values ofaverage coordination number of atoms and the average bond length Nanoclusters with even numberof atoms are more stable because of their closed electronic shell and among even clusters two andeight atomic systems were found as magic numbers of pure Cu Copper On the other hand Althoughbulk Copper is a non magnetic material we observe that clusters with odd number of atoms have afinite magnetic moment It is a kind of atomic like magnetism which is originated from the uncom pensated spin moment of a single unpaired electron of Copper The calcaluted electronic propertiesincluding ionization potential electron affinities and chemical hardness confirm the more stability ofthe even nanoclusters In order to improve the catalyses properties of the Copper nanoclusters thesenanoclusters are alloyed with palladium Hence the effect of substituting one or two Palladium atomsin the two through nine atomic pure nanoclusters and then the structural electronic vibrational andmagnetic properties of the alloy nanoclusters were studied It was observed that average bond lengthof nanoclusters of Cun 1 P d and Cun 2 P d2 are more than the corresponding values in the pure cop per nanoclusters The theoretical magic numbers of Cun 1 P d and Cun 2 P d2 were found to be 3 7 and 3 4 8 more over we observed that stable Cun 2 P d2 clusters are made of Cu2 P d2 pyramidand consequently Pd atoms in Cun 2 P d2 tends to bond togetherKeywords Density functional theory Cu cluster Cun 1 P d and Cun 2 P d2 clusters Numerical atom centred or bitals FHI aims

جواد هاشمي فر

هادي اكبرزاده

مهدي رنجبر