پديد آورنده :
نجارزادگان، مجتبي
عنوان :
بررسي خواص ساختاري، الكتروني، مغناطيسي و ارتعاشي خوشه هاي (6-1= Fen-1,FeN(N توسط نرم افزار محاسبات كوانتومي FHI-aims
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
جواد هاشمي فر
استاد مشاور :
هادي اكبر زاده
توصيفگر ها :
نظريه ي تابعي چگالي , اوربيتال هاي عددي جايگزيده ي اتم مركز , نانو ذرات مغناطيس آهن تصحيح بس ذره اي GW , جذب اتم طلا
تاريخ نمايه سازي :
18/7/90
استاد داور :
فرهاد شهبازي، پيمان صاحب سرا
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Study of Structural Electronic Magnetic and Vibrational Properties ofFeN and FeN 1Au N 1 6 Clusters by Quantum Computational Software FHI aims Mojtaba Najarzadegan m najarzadegan@ec iut ac ir 2011 04 19 Department of Physics Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Dr S Javad Hashemifar hashemifar@cc iut ac irAbstractThe potential applications of nanostructures and nanoparticles have attracted great attention in modernscience and technology Among these low dimensional systems small atomic clusters of transition metalelements display interesting physical and chemical properties Iron magnetic clusters are a group oftransition metal clusters that because of their partially occupied d orbital exhibit challenging physicalbehavior from experimental as well as theoretical point of view In this project we study the physicalproperties of iron clusters in the framework of density functional theory by using the full potentialnumerical atom centered orbital technique implemented in FHI aims computational package Because ofthe localized atom centered orbital basis set used in this code it is very efficient for accurate computation ofthe molecular and cluster structures At the first stage the accuracy parameters were optimized and thevalidity of the optimized results obtained by aims was verified by calculating and comparing the iron bulkproperties within aims and wien2k codes Then after full relaxation of the atomic positions the structural electronic magnetic and vibrational properties of FeN N 1 6 clusters were calculated It was understoodthat in the high symmetry isomers with orbital degeneracy the Jahn Teller effect plays an important role indetermining the ground state structure of the system The results show that the ground state isomers arethree dimensional and highly bonded structures with higher average atomic magnetic moment than the bulkvalue In general by increasing the number of cluster atoms their various physical properties approach thebulk values By applying the many body based GW correction we obtained very good ionization potentialsand electron affinities for Fe clusters compared with the experimental data In addition to the GW method we also determined the ionization potentials and electron affinities by calculating the Kohn Sham totalenergies of the natural and charged clusters The observed agreement between these two approachesconfirms validity of the total energies obtained by the Kohn Sham scheme After calculating the clustersvibrational frequencies their infrared spectra were obtained The infrared spectra are assumed to be thevibrational fingerprints of molecules and clusters and are very helpful in determining the structure of nanosystems experiment In order to avoid agglomeration and oxidation of iron clusters in practical situations usually they are coated by gold atoms As a preliminary step toward understanding the effects of coatingwith gold we studied the stability magnetic properties and the tendency to oxidation of the Fe clustersadsorbed by one Au atom The results show that addition of one Au atom enhances stability of Fe clusterswithout considerable change of magnetic moments Moreover we observed that the Au head of the Fe NAuclusters does not prefer to adsorb an oxygen atom This observation confirms the oxidation resistance of theAu coated Fe clusters In addition by calculating the HOMO and LUMO energy levels of FeNAu N 1 5 clusters after GW corrections we observed that the energy gap of these clusters have low sensitivity to thecluster size Keywords Quantum computations Density functional theory Localized numeric atom centered orbitals FHI aims software Iron magnetic nanoparticles GW many body correction Gold atomadsorption Oxygen atom adsorption
استاد راهنما :
جواد هاشمي فر
استاد مشاور :
هادي اكبر زاده
استاد داور :
فرهاد شهبازي، پيمان صاحب سرا
