Excitation of theNa(3p)Level byH−Ions andH0Atoms

Cross sections are reported for the excitation of Na atoms from the ground level to the $3p$ level by 1-25-keV incident ${\mathrm{H}}^{-}$ ions or ${\mathrm{H}}^0$ atoms. The cross section for excitation by incident ${\mathrm{H}}^{-}$ rises from 1.4×${10}^{-15\mathrm{}}$ ${\mathrm{cm}}^2$ at 1 keV to a maximum of 3.8×${10}^{-15\mathrm{}}$ ${\mathrm{cm}}^2$ at 15 keV and then falls to 3.6×${10}^{-15\mathrm{}}$ ${\mathrm{cm}}^2$ at 25 keV. The cross section for excitation by ${\mathrm{H}}^0$ falls from 1.3×${10}^{-15\mathrm{}}$ ${\mathrm{cm}}^2$ at 1 keV to 2.7×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ at 25 keV. These cross sections are compared with previously measured cross sections for excitation of Na by protons and electrons.