4B7 - Precision spectroscopy of new infrared emission system of molecular nitrogen

Stimulated emission and laser oscillation resulting from transient population inversions on a number of electronic transitions of molecular nitrogen have made it possible to more accurately specify energy differences between several excited singlet states of the molecule and in one case, that of the
w ^{1}\Delta_{u}
state, to more directly determine its absolute position with respect to the electronic ground state. Measurement accuracy has been improved on a system which we previously reported. A new emission system has been identified as resulting from transitions between the
w ^{1}\Delta_{u}
state and the
a^{1}\Pi_{g}
state. We have observed for the first time in the unperturbed region at low
J
values Λ doubling in
\upsilon = 0
of
a^{1}\Pi_{g}
. Very complex emission systems of more than eighty lines falling into four groups between 5.35 μm and 8.06 μm have been observed. No identification has yet been made.