Knowledge Bank

The Vagard-Kaplan A $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma u+\to X\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma g+$ omission system of $N2$ in solid argon has been excited by 10 keV electrons, at $N2$ concentration in the 0.03 to 38 range, and at temperatures of T= 5K and 24K. The spectrum consists of doublet bands originating in vibrational levels $v\prime \le 6$. Whereas Tinti and $Robinson1$, using X-ray excitation, measured exponential decays of the $\upsilon \prime \le 5$ levels which indicate a vibrational cascade $\upsilon \prime =6\to 5\to 4\to 3\to 2\to 1$ with rates of the individual steps depending on $\upsilon \prime$, on $N2$ concentration, and on temperature. Moreover, the two peaks of the spectral doublets belong to two separate cascading systems with very different cascading rates. The effect is presumably due to site-dependent vibrational energy transfer to another molecular species.