| Popis: |
Nitrogen plasmas are of interest for various technological applications, and therefore their diagnostics is of importance for in situ process control. However the role of specific atomic and molecular collision processes is still to be explored for various plasma sources. We compare optical emission spectra of nitrogen plasma generated under various conditions [1-3]. Nitrogen plasma was created by radio-frequency inductively coupled electrode less discharge at low pressure, kHz atmospheric end-field type (single electrode) plasma jet and by focusing nanosecond laser pulses directly into nitrogen gas at various pressures. Each type of plasma source produces different electron energy distributions which reflect itself through numerous collisional processes on the spectral appearance of nitrogen atoms, molecules and their ions. Optical emission spectroscopy was performed by using various miniature spectrometers suitable in applications. Experimental observations were accompanied with spectral simulations that allow determination of excitation, vibrational and rotational temperatures. We discuss spectral appearance of neutral nitrogen molecules, molecular ions, atoms, ions, and continuum emission in respect to excitation conditions such as total energy input and/or discharge or laser produced plasma source. Interplay of the N2, N2 +, N, N+ spectral features is used to describe plasma sources main characteristics. References [1] A. Vesel, U. Cvelbar, M. Mozetič, N. Krstulović, I. Labazan, S. Milošević, Materiali in tehnologije 38, 3-4 ; (2004), 177-180. [2] M. Bišćan, S. Milošević, Spectrochimica Acta Part B: Atomic Spectroscopy 81 (2013) 20-25. [3] M. Bišćan, Z. Kregar, N. Krstulović, S. Milošević, Optics Communications, 315, (2014), 37-41 195 |
