The intellectual merit of the variety of projects completed under the present grant is that it has allowed the PI and her group members to explore several microscopic factors that are vital to surface coordination chemistry, using a combination of computational techniques such as electronic structure calculations based on density functional theory (DFT), and kinetic Monte Carlo and molecular dynamics simulations.  In the first place they now have an in-depth understanding of molecular pattern formation on metal surfaces: the hierarchy of bonding that conspire to make a structure stable or unstable. While the metal coordination center is primarily responsible formation of the network, the extent of interaction between the metal coordination center and the support (metal) also determines the changes in the oxidation states.  Furthermore, while the metal coordination center is technically available for adsorption and coadsorption of small molecules, the nature of bonding of these molecules is strongly affected by that of the ligand with the coordination center.  Secondly, by carrying out in depth analysis of geometrical, vibrational, and electronic structural changes that are brought about on molecular adsorption on surfaces, they have provided a deeper understanding of important phenomena such as oxidation reactions. Most importantly, their work has highlighted the role of the local atomistic environment in determining chemical properties at the nanoscale. These results are bound to have an impact furthering our understanding of surface and nanoscale chemistry.

Another project with high intellectual merit and broad impact was the development of an understanding of microscopic processes under which proteins, the functional molecular structures of nature, fold and form structures on metal surfaces. Folded structures have not been observed previously on surfaces under controlled conditions. On the other hand, much could be learned about surface coordination chemistry through systematic examination of the self-assembly of peptides on metal surfaces. As in all projects undertaken by the PI, this one was also carried out in close collaboration with experimentalists. Density functional theory based calculations  in conjunction with molecular dynamics modeling provided insights into the atomistic details of the molecular interaction, showing an induced-fit binding scheme when the folded dimer is formed. In the absence of solvent they found a hierarchy of binding strength from polar to nonpolar, manifested in a polar-nonpolar segregation which suppresses unspecific interactions at the rim of the nanostructure. This 2 dimensional folding with the demonstrated properties opens the perspective for designing sequences for fabrication of functional, folded, molecular nanostructures on surfaces.

Broader Impact:

Five graduate students (two female and three male) and two undergraduate students have benefitted from training on projects related to this grant, including close interactions with their counterparts in the research groups of the PIs experimental collaborators.  The topics covered under the grant formed the basis of the PhD thesis of 4 graduate students, two of whom have defended their thesis and are postdoctoral researchers: 1 at a university and the other at a national laboratory.  The students and postdocs have also benefitted from presentations of results at many national and regional, and a few international, conferences and workshops. Mentoring of project graduate and undergraduate students has helped in the professional development of two junior scientists: one has secured him a position as a research scientist and the other has obtained a faculty position in a 4-year college.  Both junior scientists had the opportunity to present their work at a number of conferences and publish them in high impact journals.

One senior graduate student was the recipient of the 2016 AVS Graduate Research Award and served as a member of program committee for AVS64, Focus Topic sustainability and critical materials.  He is also a member of the AVS presidential young professional council for 2016-2017.   Rahman has been engaged extensively in outreach activities, nationally and internationally.  She is serving as UCF-Site Leader for American Physical Society-Bridge Program aimed at recruiting and training physics PhD students from underrepresented minority (URM) groups and also as the Site Leader for the APS-supported PhysTEC Comprehensive Site at UCF which aims at increasing the number of physics teachers nationally.  Rahman uses her engagement in this grant as a vehicle for interaction with the public and also as a tool for recruiting of students in STEM fields. She organizes workshops in developing countries such as Pakistan and focuses on attracting young women to research in nanoscience and related STEM disciplines.  Her work in Pakistan has been supported through an NSF travel grant. Two of the graduate students who worked on the project accompanied her at participants at two workshops in Pakistan in which they led hands-on workshops in computational material design.

Last Modified: 06/28/2019
Modified by: Talat S Rahman