UV Laser Spectroscopy Using the Velocity-Modulation Technique: New Hot Bands of the B2Σ+u–X2Σ+g System of N+2

Velocity Modulation Spectroscopy of Ions

“…The Meinel system has been studied both by traditional velocity modulation techniques [116][117][118] as well as by the recent optical heterodyne magnetic resonance velocity modulation technique 11,48 discussed earlier in this review. Absorption transitions 119,120 involving B 2 Σ(u) + r X 2 Σ-(g) + near 30 000 cm -1 as well as emission transitions in the UV and far-UV regions 37 have been measured. For NH 2 + , the ν 3 fundamental band, 121 as well as hotbands 122 have been reported.…”

Strong-Field-Induced N2+ Air Lasing in Nitrogen Glow Discharge Plasma

“…In other words, when the discharge is induced, the population in N + 2 is dominated by the Boltzmann distribution, which has long been an area of interest in the field of absorption spectroscopy. [24,25] This indicates that the laser-induced populations in the 𝐴 2 𝛱 u , 𝐵 2 𝛴 + u , and 𝑋 2 𝛴 + g states of N + 2 are far from Boltzmann distribution, so that it is possible to generate the population inversion required for air lasing. As a consequence, the negative effects of the discharge on the N + 2 lasing are the result of an increased population in the ground 𝑋 2 𝛴 + g state of N + 2 induced by the discharge, which ruins the laser-induced population inversion between the 𝐵 2 𝛴 + u and 𝑋 2 𝛴 + g states, resulting in a reduction in 391-nm lasing.…”