Molecular zero-range potential method and its application to cyclic   structures
  The zero-range potentials of the radial Schrodinger equation are investigated from a point of Darboux transformations scheme. The dressing procedure is realized as a sequence of Darboux transformations in a way similar to that used to obtain the generalized zero-range potentials of Huang-Derevianko by specific choice of a family of parameters. In the present approach we stay within the framework of conventional zero-range potential method whilst the potential parameter (scattering length) is modified taken into account spectral molecular properties. This allows to introduce molecular zero-range potential once the corresponding discrete spectrum is known. The results are illustrated on example of flat cyclic molecular structures, with particular focus on a benzene molecule, which bounded states energies are first found using atomic zero-range potentials, compared with the Huckel method, and then used to introduce single zero-range potential describing the entire molecule. Reasonable scattering behavior for newly introduced potential gives a possibility to tackle many-molecule problems representing molecules as appropriate single zero-range potentials. 
Dmitry V. Ponomarev, Sergey B. Leble
cond-mat.mes-hall math-ph math.MP quant-ph