Physics Seminar
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Sabancı University Physics Seminar

Title: Is there a common underlying electronic mechanism for the functioning of metalloproteins and metalloenzymes?

Speaker: Nejat Bulut, Izmir Institute of Technology

Date/Time: April 6, 2016 Wednesday at 13:40

Place: Sabancı University, FENS G035


Metalloproteins and metalloenzymes are responsible for important catalytic functions in organisms. These organometallic molecules contain transition metal atoms and exhibit a semiconductor gap in their electronic excitation spectrum. Examples are hemoglobin which contains Fe and vitamin B12 containing Co. Here, we explore any special role the transition metal atoms have in the functioning of the metalloproteins and metalloenzymes. From the perpective of quantum many-body physics, the most appropriate model for describing the electronic properties of these molecules is the Haldane-Anderson model of a transition metal impurity in a semiconductor host. We use the Hartree-Fock (HF) approximation to determine the parameters of the effective Haldane-Anderson model for vitamin B12 and hemoglobin. We study the resulting Anderson impurity Hamiltonian by using Quantum Monte Carlo (QMC) simulations. This combined HF+QMC technique finds that impurity bound states form inside the semiconductor gap and play an important role in determining the electronic properties of these molecules. We also observe magnetic moment formation and antiferromagnetic correlations in the vicinity of the transition metal atom. In addition, we make comparisons of the HF+QMC results with the alternative density-functional theory calculations. We also make comparisons with the photoabsorption experiments on these molecules.

Short Bio:

Lise: Ankara Fen Lisesi, 1983

B.S. in Physics: Massachusetts Institute of Technology, 1987

Ph.D. in Physics: University of California at Santa Barbara (UCSB), 1991

Postdoc: UCSB, 1991-1992; University of Illinois at Urbana-Champaign, 1992-1994

Visiting faculty: UCSB, 1994-1997; Tohoku University, Japan, 2004-2008

Faculty: Koç University, 1998-2003; Izmir Institute of Technology, 2009- 

Research areas: strongly-correlated electrons, superconductivity, magnetism