A new ab initio method of calculating \(\mathsf{Z_{eff}}\) and positron annihilation rates using coupled-channel T-matrix amplitudes

  • P. K. BiswasEmail author


We present a new ab initio theoretical formulation to calculate \(Z_{\it eff}\) and hence the positron annihilation rates directly from the onshell and offshell (half) scattering amplitudes. The method does not require any explicit use of the scattering wave function and is formally exact within the framework of the well established Lippmann-Schwinger equation. It could serve as an effective tool as all the T-, K-, and S-matrix formulations, yield directly the scattering amplitudes; not the wave function. Numerical test of the method is presented considering sample static calculations in positron-hydrogen and positron-helium systems.


Wave Function Static Calculation Numerical Test Theoretical Formulation Positron Annihilation 
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© Springer-Verlag Berlin/Heidelberg 2004

Authors and Affiliations

  1. 1.Departamento de FísicaInstituto Tecnológico de AeronáuticaCTA São José dos CamposSP, Brasil
  2. 2.Divisão de Engenharia Biomédica, Instituto de Pesquisa e DesenvolvimentoUniversidade do Vale do ParaibaSão José dos CamposSP, Brasil

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