Knowledge Bank

Extensive spectra attributable to n$\ell \lambda (3\Pi g,3\Sigma g+)\leftarrow a3\Sigma u+$ for $Ar2$ have been observed by laser excitation spectroscopy in the afterglow of a pulsed discharge. The 5p$\pi$ $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi g+\leftarrow$ a $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma u+$ and 7p$\sigma$ $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma g+\leftarrow a3\Sigma u+$ transitions observed near $19823cm-1$ and $19529cm-1$, respectively, exhibit many bands with ^{\prime}{v} -O in their $(v\prime =v\prime )$ vibrational band system developments. The higher n members of these and the other observed series exhibit primarily (0-""{v}) progressions dominated by their (O-O) members. Rotational analyses of several partially resolved bands will be discussed, and the observed structures compared with their counterparts in $He2$ and $Ne2$ and $Ne2$. Vibrational intervals for $a3\Sigma u+(v\le 4$ and $7p\sigma$ $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma g+$ ($v\le 2$) yield vibrational constants $\omega a-296cm-1$ and $282cm-1$ $x\omega -2.5cm-1$ and $17cm-1$, respectively. The ionization potential is found to be $29373\pm 3cm-1$ based on a $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma u+(v=o)$.