LSM - Seminars: January 2008 Archives

Seminars Archives

December 2007 | January 2008 | February 2008

Thursday, January 24, 2008
Ferroelectric Oxide Surfaces: Cutting Edge Chemistry Prof. Andrew Rappe Deparment of Chemistry University of Pennsylvania 12:00 PM Room 260, Wright-Rieman Chemistry Laboratory Abstract: The surfaces of ferroelectric ABO oxides are charged due to the bulk material polarization, and this surface charge leads to exotic surface chemistry. In this talk, three illustrations of this effect will be presented. 1) In LiNbO3 the polar stacking of ionic layers combines with ferroelectricity to make the intrinsic surfaces nonstoichiometric. 2) With BaTiO3 flipping the ferroelectric polarization changes the sticking coefficient for incoming molecules. 3) For PbTiO3 supported Pt, the oxide polarization strongly affects chemisorption and reactivity on Pt. These examples underscore the message that surface chemistry can be dramatically influenced by tailoring the bulk ferroelectric properties of the support.

Thursday, January 24, 2008

Ferroelectric Oxide Surfaces: Cutting Edge Chemistry
Prof. Andrew Rappe
Deparment of Chemistry
University of Pennsylvania
12:00 PM
Room 260, Wright-Rieman Chemistry Laboratory

Abstract: The surfaces of ferroelectric ABO oxides are charged due to the bulk material polarization, and this surface charge leads to exotic surface chemistry. In this talk, three illustrations of this effect will be presented. 1) In LiNbO3 the polar stacking of ionic layers combines with ferroelectricity to make the intrinsic surfaces nonstoichiometric. 2) With BaTiO3 flipping the ferroelectric polarization changes the sticking coefficient for incoming molecules. 3) For PbTiO3 supported Pt, the oxide polarization strongly affects chemisorption and reactivity on Pt. These examples underscore the message that surface chemistry can be dramatically influenced by tailoring the bulk ferroelectric properties of the support.

Thursday, January 31, 2008
Stacking interactions and the Twist of DNA Valentino Cooper Physics Department Rutgers University 12:00PM, Room 260, Wright-Rieman Chemistry Laboratory Abstract: The interactions between stacked nucleobase pairs contribute significantly to the stability of DNA. In addition, numerous studies highlight the stabilizing effect of thymine within DNA. As such knowledge of the relative importance of these interactions may be useful for developing a complete theoretical understanding of DNA. I will present our use of the vdW density functional, (Dion, Rydberg, Schröder, Langreth, Lundqvist, PRL 92, 246401, 2004) to investigate the importance of stacking interactions between Watson-Crick DNA base pairs. I will discuss the relative accuracy of this functional for simulations of stacked nucleobases and our application to stacked nucleobase pair steps, a system which is not possible to study using traditional quantum chemical methods. These results indicate that stacking interactions are essential for defining both the base pair step distance and the helical twist angle of DNA. Furthermore, we show that the stability gained from the presence of thymine is due to vdW interactions between the methyl group of the thymine with neighboring bases.

Thursday, January 31, 2008

Stacking interactions and the Twist of DNA
Valentino Cooper
Physics Department
Rutgers University
12:00PM, Room 260, Wright-Rieman Chemistry Laboratory

Abstract: The interactions between stacked nucleobase pairs contribute significantly to the stability of DNA. In addition, numerous studies highlight the stabilizing effect of thymine within DNA. As such knowledge of the relative importance of these interactions may be useful for developing a complete theoretical understanding of DNA. I will present our use of the vdW density functional, (Dion, Rydberg, Schröder, Langreth, Lundqvist, PRL 92, 246401, 2004) to investigate the importance of stacking interactions between Watson-Crick DNA base pairs. I will discuss the relative accuracy of this functional for simulations of stacked nucleobases and our application to stacked nucleobase pair steps, a system which is not possible to study using traditional quantum chemical methods. These results indicate that stacking interactions are essential for defining both the base pair step distance and the helical twist angle of DNA. Furthermore, we show that the stability gained from the presence of thymine is due to vdW interactions between the methyl group of the thymine with neighboring bases.

You may also view a summary of past and upcoming seminars.

Laboratory for Surface Modification (LSM)

Rutgers University

Menu

Seminars Archives