Configuration interaction calculations of annihilation rates for positronic complexes of alkali hydrides

Neural network variational Monte Carlo for positronic chemistry

“…Theoretical calculations of positron binding energies and annihilation rates have been performed using many of the standard tools of computational chemistry. Positron binding to atoms and molecules has been studied using wavefunction expansions in explicitly correlated Gausians with the stochastic variational method (ECG-SVM) [16][17][18][19][20][21][22][23][24] , configuration interaction (CI) methods [25][26][27][28][29][30][31] , and quantum Monte Carlo (QMC) methods [32][33][34][35][36][37][38][39][40] . The annihilation rate and lifetime of positrons in solids, particularly in the presence of defects, has been studied using density functional theory 41,42 and quantum Monte Carlo methods 43,44 .…”

“…This results in very slow convergence of CI calculations with the maximum angular momentum of functions included in the basis. Furthermore, the positronic density is typically highly diffuse, requiring the augmentation of standard basis sets with additional diffuse basis functions 27,[29][30][31] .…”