Knowledge Bank

“The 600 \AA band of $He2$, produced with an uncondensed discharge in helium, was studied at room temperature and at liquid nitrogen temperature. A densitometer trace of the band shows intensity fluctuations with fifteen peaks extending from about 600 to 790 \AA. When the discharge was operated at liquid nitrogen temperature, the peaks showed a slight wavelength shift toward the longer wavelengths. It is suggested that the band is produced ill the transition $A1\Sigma u+-X\prime \Sigma g+$ and that, it originates in highly excited vibrational levels of the A-state. Such a highly excited molecule would be produced by two colliding atoms, one in the $ls2\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}S0$ state, the other in the $ls2s1S0$ state., as they pass through the potential hill which was calculated by Buckingham and $Dalgarno.1$”