EXCITATION OF THE CA ATOM FROM THE METASTABLE STATES BY ELECTRON-IMPACT

Electron impact excitation of the Ca atoms from the metastable 4s4p P- 3(J) states has been studied by an optical method in crossed atomic an d electron beams in the energy range from threshold up to 30 eV. The r elative excitation functions and the absolute values of the emission c ross sections for 16 spectral transitions excited both from the metast able and ground states have been obtained. The experimental results ar e compared with the close-coupling and Born-Ochkur calculations carrie d out with the extensive many-configuration target wavefunctions. In m ost cases the theoretical excitation functions agree within the limits of experimental error (50%) with the experimental results including t he resonance-like structure in the near-threshold region allowing us t o classify uniquely the resonances observed.