Knowledge Bank

Calcium diatomic molecules were produced in a heat-pipe oven at temperatures from $1000-1200\circ K$ . Photoluminescence of $Ca2$ has been studied with various laser sources and with white light. Discrete, sharp line spectra are attributed to known bound states of $Ca2$. A broad continuum emission with an oscillatory intensity distribution is associated with emission to the repulsive part of the lower state. A weak continuum emission to another repulsive state also has been observed. The observed strong emission from the atomic resonance line at 422.7 and 657.3 nm probably is caused by dissociation of excited $Ca2$ molecules. The laser-excited photoluminescence experiments suggest that the ground state of $Ca2$ is repulsive and that the lowest observed bound state of $Ca2$ correlates with the $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}p$ atomic state.