Experimental investigation of the population of the rotational levels of molecules in a free jet of nitrogen

Aerodynamic applications of underexpanded hypersonic viscous jets

“…The computation results, based on the quantum concept of rotational energy exchange, correlate well with the experimental data. 21 The classical model 25 -26 predicts the values of T R , which do not correlate with experimental ones. The temperature distribution 22 in the isentropic expansion (i.e., E R = T, and y = 1.4) of nitrogen from a circular sonic 100 10 10 100 r/r.…”

“…The experimental results for T R along the axis of a nitrogen jet were obtained by Marrone 20 (marker x) and Borzenko et al 21 (triangles). The results were discussed in the study of Lebed and Riabov.…”

“…Marrone 20 and Borzenko et al 21 studied the translationalrotational (R-T) relaxation in the expansion of a molecular gas into a vacuum. A significant drop in the gas density downstream leads to a decrease in the number of molecular collisions and as a result, the departure of the rotational energy S R from the equilibrium value e°R is observed.…”

The rate of collisional quenching of N2O+ (B 2Σ), N+2 (B 2Σ), O+2 (b 4Σ), O+ (3d), O (3p), Ar+ (4p′), Ar (4p,4p′) at the temperature ≤200 K

“…55 The scheme of the flow formation and equipment for electron-beam measurements is shown in Fig. 1 and includes the vacuum chamber ͑1͒, the source of the gas jet ͑2͒, the electron beam ͑3͒, and spectrometric equipment ͑4͒.…”

Rotational relaxation in gases

“…In a series of experiments carried out from the early 1970s [28,36,37] it has been established that the rotational energy distribution in an ultrasonic jet of expanding gas is a nonequilibrium distribution. Although population inversions of the rotational levels were not observed in these experiments, the study of rotational relaxation through the rotational distribution in an ultrasonic expansion of gas has been demonstrated as an important technique and has obtained a wide following.…”