Determination Of Enhancement Factor Of Electron-Positron Annihilation In Metal Cu(FCC)

The electron-positron annihilation rates can be calculated directly from their densities in the annihilation rate function. However, these values are smaller than the experiment values. The deviation is result of the local increase of the electron density around the vicinity of positron. To correct this deviation, it is necessity of introducing the factor, known as the enhancement factor into the annihilation function which pointed out the long attractive electron-positron interaction. In this article, the density functional theory (DFT) and quantum Monte Carlo method (QMC) are applied to calculate the enhancement factor g(n+,n-,0) of electron-positron in metal copper with FCC structure. In our calculation, the factor g(n+,n-,0) is about 6.42. This value agrees with the results of Barbiellini, Boronski, and Brand. (author)