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Reminder: Harvard CCB & ITAMP Joint Quantum Seminar this Friday



The Department of Chemistry & Chemical Biology (CCB) and Institute for Theoretical Atomic, Molecular & Optical Physics (ITAMP) at Harvard University are co-sponsoring a seminar series on quantum science and chemistry.  The first seminar is this Friday, September 21 at 4:15pm in Pfizer Lecture Hall, Mallinckrodt Building, 12 Oxford Street, Cambridge.  Refreshments will be provided at 4pm.


Professor Joshua Schrier from Haverford College (http://www.haverford.edu/chemistry/schrier/) will be presenting.  His talk information is below.


Quantum Chemical Engineering:  The feasibility of isotope separation using quantum tunneling effects in nanostructures.

Membrane-based gas methods are potentially more energy efficient than adsorption and cryogenic distillation for the separation of gases, and are being adopted for a number of applications.  Because classical membrane permeance is inversely proportional to membrane thickness, the theoretical maximum is reached for membranes that are only a single molecular layer thick, leading to recent theoretical and experimental work on two-dimensional polymers and nanometer-sized pores in graphene.  Besides the possible technological improvements, new types of transport mechanisms occur with these two-dimensional membranes.  In particular, because of the thinness of these materials, quantum tunneling of atoms and molecules can become an important contributor transport.

In this talk, I will discuss our ongoing computational efforts to identify nanostructures which display atomic quantum tunneling phenomena, with a specific application to helium isotope separation. I will then describe our recent theoretical work on a temperature-driven "though experiment" which enables us to distinguish between tunneling and classical transport.  In addition to practical simplicity, the direction of the isotope concentration can provide a direct confirmation of tunneling, and the effect is large enough to be measured using a simple gas density balance. Finally, I will discuss our recent progress on the use organometallic assemblies to create double-barrier potentials that display resonant tunneling of the helium atoms.