Extended shell model calculation of the T=0 natural parity spectrum of 4He

The ground state and the first excited state of 4He are calculated in a complete 10hw shell model basis using the potentials of Volkov and Brink and Boeker. The 1-, 2+ and 4+ T=0 states are also investigated, respectively, up to 9, 8 and 6hw. It is found that the agreement with experiment is significantly improved when the model space is enlarged.