In this thesis the structural, elastic and electronic properties as well as electric eld gradient of the strongly correlated intermetallics LnX3 (Ln = La-Gd, X = In, Sn) have been investigated by using the full potential linearized augmented plane wave plus local orbital (FP-LAPW+lo) method within the framework of density functional theory. The structural properties of these compounds are calculated by LDA, GGA, meta-GGA, WC, B3PW91, LDA+U and GGA+U schemes. The calculated lattice parameters are found consistent with the available experimental results. Our results show contraction of lattice constant along the series and the divalent state of Eu is also veri ed. The itinerant and localized behavior of electrons in f -states of these compounds is also discussed. These compounds have 4f orbitals and hence strong electron-electron correlation e ect is expected, therefore, the electronic properties are also calculated with the Hubbard potential U (GGA + U and LDA + U) and the e ect of Hubbard potential on the density of states is discussed in details. The relativistic e ects are also considered by including the spin-orbit coupling (SOC). The spin-orbit coupling predict the correct electronic properties and also reveals the splitting of 4f states of the rare-earth elements. It a ects the band structures of the compounds and induces non-degeneracies in some degenerate states in the vicinity of the Fermi level. Furthermore, the SOC e ect increases from left to right in the lanthanide series in the LnIn3 and LnSn3, which shows interesting nature of SOC e ect in the periodic table. The elastic constants of these compounds are also calculated. Our calculated values for the elastic constants of the compounds are closer with the available experimental values as compared to the other theoretical results. The mechanical properties for the compounds under studies such as shear iii modulus, bulk modulus, Young''s modulus, Kleinman parameters, anisotropic ratio, Poisson''s ratio, Lame''s coe cients are also determined . The Cauchy pressure and B/G ratio are also investigated to evaluated the ductile and brittle nature of LnIn3 and LnSn3 compounds. The Sound velocities for shear and longitudinal waves, and Debye temperature also explored on the basis of mechanical properties. The Electriceld gradients (EFG) are also calculated for the rare-earth intermetallics LnIn3 and LnSn3 (Ln = La, Ce, Pr and Nd) using the GGA, GGA + U, as well as GGA + SOC. Our results show that the EFGs calculated by GGA+U approach are in better agreement with the available experimental values of the M ossbauer spectroscopy as compared to the other theoretical schemes. Our results show nonzero EFGs at rare-earth sites in the AFM phase. The present research will add some theoretical understanding of these materials and will alsoll the gap about some of the physical properties of these compounds in literature.
آئوچھو لوآسمان نحمدہ ونصلی علی رسولہ الکریم امّا بعد فاعوذ بااللہ من الشیطن الرجیم بسم اللہ الرحمن الرحیم معزز اساتذہ کرام اور میرے ہم مکتب ساتھیو! آج مجھے جس موضوع پر اظہار خیال کرنا ہے وہ ہے:’’آئو چھولو آسمان ‘‘ صدرِذی وقار! آسمان بلندی و عظمت کی علامت ہے، عروج و ترقی کی علامت ہے، مجدی و سروری کی علامت ہے، آسمان کے ذکر سے مقام و مرتبہ مراد لیا جارہا ہے، آسمان کی مثال سے غرض و غایت علو مرتبت ہے، آسمان تک رسائی گویا ترقی و عروج کی معراج ہے۔ صدرِمحترم! ہمیں عظمت کے حصول کے لیے غفلت و لاپرواہی کے پردے کو تار تار کرنا ہو گا۔ تساہل و کسلمندی کے حصار سے باہر آنا ہوگا ،سستی اور بے کاری کے رجحان کی نفی کرنی ہوگی ، اخلاقی گراوٹ کی غلاظت کی سٹرانڈ سے بچنا ہو گا، زندگی کے تمام پہلوئوں میں مثبت تبدیلی لانا ہوگی۔ جنابِ صدر! حصول عظمت کی خاطر انتھک محنت کرنا ہوگی ، سلف صالحین کے طریقے اپنانے ہوں گے، دھوکہ دہی ، فریب کاری، کذب بیانی ، ڈاکہ زنی ، زنا کاری ، رشوت ستانی،اقرباء پروری جیسی قبیح عادات سے اپنے دامن کو پاک و صاف رکھنا ہو گا۔ جسم کی صفائی کے ساتھ ساتھ اپنے روح کی بھی طہارت کا انتظام کرنا ہوگا۔ عقابی روح جب بیدار ہوتی ہے جوانوں میں نظر آتی ہے ان کو اپنی منزل آسمانوں میں جنابِ صدر! جن نابغۂ روزگار ہستیوں نے اپنے دامن کو منزّہ مطہر رکھا، جنہوں نے سلف صالحین کے نقش قدم پر چل کر اپنی منازل کا تعین کیا، جنہوں نے ہرلمحہ اپنی زندگی کی گاڑی کو شارع اسلام پر رواں دواں رکھا، ان کا طائر علومرتبت فلک کی بلندیوں پرمحو پرواز ر ہا۔ ان کے علم و دانش کا آفتاب و ماہتاب آسمان کی...
خطۂ بہاول پور کے چند مغربی اسفار(ایک نو آبادیاتی باشندے کی نظر میں) Where the western colonial powers have had a profound influence on other forms of literature, such a genre of travel journalism in the Bahawalpur region could not be safeguarded. The region is known for its civilization and culture, yet the rumors that have been written from Pakistan to Pakistan remain mournful that the tradition under the influence has stirred. Although the nature of the journals being written in the Bahawalpur region varied, the correspondents here discussed the impact that the west had given them. At the national level, the ambassadors sought for western couples and also showed an attitude of disregarding civilization and culture. At the national level, the ambassadors sought for western couples and also showed an attitude of disregarding civilization and culture. Travelling entrepreneurs separate from their country apart from a new angle and independent thinking, they seem to be lacking in the west. This difference can be seen even more clearly if domestic and international travels are taken into account.
The main focus of the present research is the development of efficient catalysts for the degradation of wide range of pollutants present in different environmental compartments. For this purpose, two sets of compounds are synthesized. One class is designated as quantum dots and the second is sulphide based nanoparticles on the basis of particle size. The potential of these materials as candidates for environmental remediation is evaluated through degradation studies of dyes, polyaromatic hydrocarbons and pesticides. Quantum dots were synthesized to act as core (indium phosphide), shell (zinc sulphide) and (silver & copper) doped following the thermal decomposition process. Another series of compounds based on zinc and silver sulphide was attempted. The structure property relationship was assessed through a wide range of techniques including UV-Visible spectroscopy (UV-Vis), Photoluminescence spectrofluorometry (PL), X-ray Diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM) and Thermogravimetry (TGA). The particle size results obtained from TEM supported two ranges; 2.28-4.60 nm and 612 nm for quantum dots and sulphide based nanoparticles, respectively. Each material was spherical in shape with clear lattice fringes. The purity of the product was witnessed by the presence of main elements and doping was in proportion to concentration induced. XRD results of ZnS depicted lattice planes (111), (200), (220), (311), (400), and (331) in good agreement with cubic geometry. It was also found that doping stamped good thermal stability to the synthesized material. Each of the synthesized material was tested as potential photocatalyst candidate for the degradation of representative dyes (crystal violet, Congo red), polyaromatic hydrocarbons (phenanthrene, naphthalene and pyrene) and pesticide (deltamethrin). For this purpose, series of bench scale batch experiments were designed and photocatalytic activity under UV light irradiation was followed on UV-Visible, Gas chromatography coupled with Mass spectrometry, and High performance liquid chromatography.The degradation potential of QDs due to smaller particle size was higher than nanoparticles with optimum efficiency of 95% and 81%, respectively, for both cationic and anionic dyes. The results indicated that degradation of PAHs increased with increase in irradiation time as evident from the reduced intensity of molecular ion peaks at standard retention times.The fragment at m/z 149 represented formation of phthalic acid that is less hazardous than parent compound. The study concludes that each synthesized material can be employed as potential photocatalyst for the degradation of representative pollutants. It is recommended that environmental compartment with mix pollutants can conveniently be treated with a single material to an appreciable extent. The study offers economical and environment friendly remediation model.