Hello everyone,

I am looking for an ab initio toolkit/platform/package to calculate the effect of the positrons on the molecular structures before the occurrence of electron-positron annihilation. I was wondering if this is possible through codes such as CPMD, VASP, Gaussian, … perhaps by adding an auxiliary particle and/or defining positron as a hole (the way that we treat electron-hole pair in terms of excitons) …

I appreciate your advice in advance,

Ramin.

Hi @Ramin_Abolfath,

None of the standard electronic structure codes support this, to the best of my knowledge. Most DFT codes are built around a “one-component” quantum mechanical formalism, which only treats electrons.

Really important to recall here that positrons only emerge from a solution of the Dirac equation, and not from the Schrodinger equation. Most standard DFT codes start from the Schrodinger equation.

You might want to look for a “two-component” formalism code (which explicitly treats electrons and positrons) or a code that explicitly solves the Kohn-Sham-Dirac equation

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