Antisymmetrized Molecular Dynamics with Coherent State Pion and Its Application to Excited Spectrum of 12C

We have introduced coherent state neutral pion into Antisymmetrized Molecular Dynamics. With the aid of coherent state technique, it becomes possible to calculate transition matrix elements of the pion field operator and to study excited states containing pions. For large pion-nucleon coupling fpiN > 1.6, pions have a finite expectation value and bring large energy gain in 12C. We discuss two aspects of pionic effects in spectroscopy; the LS interaction like effect and the mixing of different nucleon parity states, which would modify low energy nuclear levels.