M.Phil / MS
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/30
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Theoretical Studies of Superalkalis Doping on Calix[4]arene; A Unique Approach for the Improvement of Nonlinear Optical Response(Library Information Services COMSATS University Islamabad Lahore Campus, 2023-02-27) Khalida Khalil; FA21-R06-024; Dr. Mazhar Amjad Gilani; LHR TP 8454Many scientists are interested in developing high-performance nonlinear materials because of their potential uses in areas such as optics, optoelectronics, optical computing, and others. Density Functional theory (DFT) is used to predict NLO response of the selected systems. The study revealed that the doping of superalkalis on calix[4]arene is an efficient strategy to design high performance NLO materials. The interaction energy (Eint) calculations are used to analyze the thermal stability of the complexes under consideration. Superalkali doping generates diffuse surplus electrons, which produce the alkalide properties in the corresponding systems. Through static and dynamic hyperpolarizability investigations, these alkalides are further studied for their nonlinear optical (NLO) responses. The large values of second (5.9×105) and third-order (1.9×108) NLO responses at 1200 nm, along with a high refractive index, demonstrate that the NLO response of the corresponding complexes increases at large wavelength. The nature of charge transfer was confirmed by the NBO analysis. The weak electrostatic interactions between calix[4]arene and superalkali was revealed through QTAIM and interaction region indicator analysis (IRI). The TD-DFT calculations confirmed the transparency of these superalkali (Li3O, Na3O and K3O) doped complexes in UV-VISIBLE regions. Overall, the study highlights the M3O@calix[4]arene as potential candidate for designing high performance NLO materials.Item Hydrogen Splitting using Single Metal Atom Doped Zinc Oxide Nanocage as a Catalyst: A DFT Study(Library Information Services COMSATS University Islamabad Lahore Campus, 2023-02-26) Ali Hussain; FA21-R06-016; Dr. Mazhar Amjad Gilani; LHR TP 8447Hydrogen dissociation reaction is a key step in sustainable, non-toxic and renewable energy production and single atom catalysts have shown promising catalytic activity in facilitating this reaction. The world is currently facing major challenges related to the environment, including climate change and the depletion of non-renewable energy sources. As a potential solution to these challenges, the use of clean and renewable energy sources, such as hydrogen, has gained increasing attention. Herein we employed DFT calculation on single atom catalyst-based study to investigate the adsorption and dissociation of H2 molecule over TM@ Zn12O12 catalysts. The analysis of the interaction energy reveals the stability of all transition metal doped complexes (Sc-Mn), with the highest interaction energy (-4.27 eV) observed in the Cr@Zn12O12 complex. Furthermore, electronic properties (FMOs, NBO analysis) confirm the electropositive nature of transition metal atoms. QTAIM and IRI analysis are employed to interpret shared or partially covalent interactions in TM@ Zn12O12 complexes. The mechanism of hydrogen dissociation reaction is studied for all the complexes (Sc-Mn), and it is found that Sc@Zn12O12 is the most efficient catalytic agent for the hydrogen dissociation reaction, with the lowest activation barrier (0.09 eV). EDD isosurface and NBO analysis confirm the charge transfer from metal to antibonding orbital of hydrogen which facilitates the hydrogen splitting. The pivotal insights gained from this study enhance our understanding about the stability, electronic properties, and hydrogen dissociation reaction of various transition metal doped Zn12O12complexes.