Coolaboration with Claudio

De Física Computacional
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Role of anharmonicity and asimmetry of dimer potential

1) Study anharmonic asimmetric potential: V(x)=0.5*k*x**2-beta*x**3/3

-Understand why anharmonicity destroys hysteresis. -Is there a resonance? -Negative differential mobility near resonance?

Find parameters for Lennard-Jones interaction that mimicks the anharmonic asimmetric potential

2) Study anharmonic simmetric potential V(x)=0.5*k*x2+beta*|x3|/3

3) Double well potential V(x)=alpha*x4-beta*x2

Transition between different states due to resonance


Excitation of internal vibrations (up to dissociation) by moving the substrate

1) 1D dimer

Consider "oscillating" substrate potential of the form

  V_sub(x,w)=U*cos(2pi/a*(x+x0*sin(wt)))

Is there a resonance frequency w for which dimer internal motion is excited?


2) 2D cluster of nanoparticles on a substrate (connection with experiment of Spasova: Co nanoparticles on metal substrate)

Idea: experimentally the nanoparticles form a triangular arrangement on the substrate, but it is desirable to have a uniform coverage. We could probably show that, by exciting a resonance in the cluster, the nanoparticles could dissociate and be pushed away from each other, thus balancing their tendency to clusterization.

At first we can study a model system of LJ particles and see what the equilibrium configuration is and what happens if we move the substrate.