TQRB · Tunneling quantum roto-breathers (TQRB)

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Project objective

The main objective of the proposed research is to develop a rigorous mathematical theory to study the dynamics of tunneling quantum roto-breathers (TQRB) in molecular crystals. It is intended to use a new theory to explain the experiments, that were performed by Fillaux, Carlile and Kearley in 1990-98 on 4-methyl-pyridine molecules using recording of inelastic-neutron-scattering (INS) spectra. A mathematical definition of TQRB in terms of superposition of tunneling rotons is to be constructed. A recently developed theory, by Prof MacKay, of spectral projections and quantum discrete breathers is to be engaged to develop a theory for the dynamics of rotating methyl groups. A theory for tunneling rotons is to be developed in this aspect. A parametric fit is to be performed to compare our theoretical results with the experimental data. Numerical simulations are to be performed to study the dynamics of such discrete breathers in molecular arrays. Estimations of the most relevant couplings of methyl groups in a molecular array and their order of strength are to be performed. Persistence of spectral projections is to be studied in these aspects. Deduction of the consequences of coupling on the bottom of the spectrum and on width of spatial corrections will be carried out: for one dimensional chains of molecules and in realistic networks; for the isotopically pure cases and for isotopic mixtures.

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Participants

• UNIVERSITY OF WARWICK · COVENTRYCoordinatorUnited Kingdom

Links

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