Enhancement of O-atom density through collisions with Ne by laser-produced plasma in Ne–O2 gas mixtures and possible energy transfer mechanism

Abstract

Laser-produced plasma in Ne and O2 gases and Ne–O2 gas mixture with different O2 fractions have been investigated. The plasma were produced by focusing a laser beam of 5 ns pulse duration from a Nd:YAG laser ([Formula: see text] = 1064 nm) through a lens of 5 cm focal length into the chamber filled with different gas species at different pressures. Possible enhancement in O-atom densities through collisions with metastable Ne atoms by the laser-created plasma in Ne–O2 gas mixtures and possible energy transfer mechanism was studied. Study of energy transfer through collisions was carried out by comparisons of the line intensities of the emitted spectra from laser-created plasma in gas mixtures and pure gases with the technique of optical emission spectroscopy (OES). Strong evidence of energy transfer from Ne to O was recorded. From the result, it was suggested that the high-lying metastable levels of Ne were responsible for enhancement of O-atoms density in gas mixture and Ne also play important role in energy transfer mechanism through collision. Also, behaviors of the line intensities under different laser energies were studied. Behaviors of line intensities and line widths were the main parameters measured. Stark broadening of lines in Ne with different laser energies was recorded. The electron temperature T[Formula: see text] and number density N[Formula: see text] were found to be 1.01 eV and 9.44 × 10[Formula: see text] cm[Formula: see text] in Ne at different laser energy/pulse with total pressure of 1000 mbar.