Path Integral Monte Carlo Study of Ground State Properties of the Lithium Atom

In this work, the path Integral Monte Carlo(PIMC) is employed to estimate the ground-state properties of the lithium atom. The three-electron system is formulated in atomic units and represented by discretized imaginary-time paths. The (1s2 2s1) electronic configuration is used to construct the antisymmetric trial state, while a Jastrow correlation function is employed to incorporate electron–electron correlations. The total ground-state energy and its kinetic and potential components are calculated together with selected structural and correlation properties. Systematic convergence investigated with is respect to inverse temperature, the number of Trotter slices, and Monte Carlo sampling, while statistical uncertainties are evaluated by considering autocorrelation and block averaging. The calculated results are subsequently compared with high-precision theoretical benchmarks and with established electronic-structure and quantum Monte Carlo methods. The study has established a theoretical and computational PIMC framework for accurate and reliable determination of the ground properties of lithium atom which can be extended to other correlated atomic systems.