پديد آورنده :
نجف وند زاده، حليمه
عنوان :
محاسبه كوانتومي خواص ساختاري، الكتروني، مغناطيسي، ارتعاشي و گرمايي نانو خوشه هاي خالص Agn و آلياژي Agn-mPdm ...
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك
صفحه شمار :
[هشت]،106ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
جواد هاشمي فر
استاد مشاور :
مجتبي اعلايي
توصيفگر ها :
نظريه تابعي چگالي , FHI-aims , نانو خوشه هاي نقره , نانو خوشه هاي آلياژي نقره-پالاديم , اندازه ي جادويي , تصحيح ذره اي GW
تاريخ نمايه سازي :
12/4/91
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Quantum Mechanical Study of the Structural Electronic Magnetic Vibrational and Thermal Properties of Agn and Agn m P dm Clusters n 9 m 1 2 Halimeh Najafvandzadeh H najafvandzade@ph iut ac ir 2 12 2012 Department of Physics Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language PersianSupervisor Dr S J Hashemifar hashemifar@cc iut ac irAbstractSilver is the metallic elements and it has been employed most extensively since ancient times tofight infections and control spoilage Recently nanotechnology is employed to increases surface tovolume ratio and consequently increases surface to volume ratio so it will increase the effective ness and reactivity of matters by producing nanoparticles Silver nanocluster are ideal candidatesfor catalysis and antibacterial applications Alloying silver with other metals such as palladium willhelp to increase catalytic properties In this thesis we applied the computer program package FritzHaber Institute ab initio molecular simulations FHI aims to study structural electronic mag netic and vibrational properties of pure silver nanoclusters and silver palladium alloy Agn 1 P d andAg n 2 P d2 nanoclusters This computational package is primarily based on the density functionaltheory although some many body corrections such as GW self energy are also involved In orderto verify the the accuracy of the FHI aims calculations structural and electronic properties of dimerand crystal of silver has been reinvestigated by using the computational package WIEN2k We ob served good agreement between the results of two packages After optimization of input parametersand selection of appropriate exchange correlation functional the Two to nine atomic silver clustersinvestigated and for each cluster more stable structures are determined The Jahn Teller effect is ob served in structural relaxation of high symmetry structures Next the average coordination numberand bond length dissociation energy and electron affinity energy ionization potential HOMO LUMOenergy gap magnetic moment and vibrational properties of the most stable clusters were calculated Finally the general trend of the effect size on these properties were investigated Calculations showthat up to size of 6 heptamer silver clusters prefer two dimensional 2D planar structures whilelarger clusters stabilize in 3D geometries we observed that by increasing the cluster size both aver age coordination number and bond length quantities as well as binding energy smoothly approach thecorresponding bulk values Presence of a pair electron in HOMO level of silver clusters with evennumber of atoms makes these systems non magnetic and also more stable than odd clusters The cal culated binding energies and second order energy differences confirm 2 and 8 as the magic numbersof pure silver clusters in agreement with experiment After determining the most stable structures ofclusters of silver palladium alloys it was seen that in the Clusters of silver alloy with one palladiumatom Agn 1 P d structural transition from two dimension to three dimension occurs at the sevenatoms cluster similar to the pure silver clusters Moreover stable atomic configurations of the theallay clusters having less than seven atoms are similar to the corresponding to the pure silver clusters On the other hand the most stable structure of alloy clusters with two palladium atoms Agn 2 P d2 at least four atoms are three dimensional structure Comparing with the literature data we observedthat atomic configuration Agn 2 P d2 clusters are similar to the corresponding pure palladium clusters our calculations show that the relative stability and consequently magic numbers of silver palladiumalloy clusters compared with the pure silver clusters has changed Keywords Density functional theory FHI aims Ag cluster AgPd cluster Magic number GW correction
استاد راهنما :
جواد هاشمي فر
استاد مشاور :
مجتبي اعلايي
