The Spin Dynamics Of Molecular Magnets

The single molecular magnet(SMM)is a new field in the condensed matter physics.It has attracted lots of interests because it can realize the quantum computation and quantum information storage.Especially the molecular V6 and V15,from our investigation,we can have a much clearer picture on the mechanics of the SMMs and the fundamental theory in quantum mechanics.In this thesis,we studied the fundamental model of the molecular V6 and V15,which is usually called the Heisenberg triangular model.In the Nuclear Magnetic Resonance(NMR) experiment,the usual chital symmetry can't explain the result of the different local spin momentums observed in vanadium particles.To explain the phenomenon of the experiment, we introduced a tensor operator(?)which can form the Yangian algebra with the spin operator S~2,S_z.Through our careful calculation,the conclusion we got that Y~2 is good quantum number which can be used to represent the state of the system.We found that only the states characterized by these quantum numbers can fit the experiment result exactly.We also gave a prediction on the NMR experiment by considering the unusual intertriangle interaction that is written in the form of a Yangian operator.In comparing with the usual NMR experiment,we discovered that the spectral in V6 NMR experiment has an additional peak at the frequency of 0,and further more the width of the spectral is broadened for this reason.