Abstract
The variational Monte Carlo method is applied to calculate the ground-state energy eigenvalues and eigenfunctions of a beryllium atom. The obtained wave functions are used to calculate the mean distance of the electrons from the nucleus and the mean distance between the electrons. The computations were carried out with the trial wave functions in the form of the Slater determinant multiplied by a correlation function corresponding to the interactions between the electrons. Two different kinds of orbital functions as well as two different types of correlation functions are used in the calculations. The obtained results of the ground-state energy eigenvalues and radii are very satisfactory when compared with the exact values and the previous findings.