Quantum Monte Carlo calculations of excited states in A=6–8 nuclei

A variational Monte Carlo method is used to generate sets of orthogonal trial functions, Ψ_T(J^π;T), for given quantum numbers in various light p-shell nuclei. These Ψ_T are then used as input to Green’s function Monte Carlo (GFMC) calculations of first, second, and higher excited (J^π;T) states. Realistic two- and three-nucleon interactions are used. We find that if the physical excited state is reasonably narrow, the GFMC energy converges to a stable result. With the combined Argonne v₁₈ two-nucleon and Illinois-2 three-nucleon interactions, the results for many second and higher states in A=6–8 nuclei are close to the experimental values.