Eur. Phys. J. D 29, 235-245 (2004)
https://doi.org/10.1140/epjd/e2004-00051-1

Theoretical and experimental CARS rotational distributions of H₂(X¹Σ_g⁺) in a radio-frequency capacitive discharge plasma

¹ Centro Laser s.r.l., S.P. per Casamassima, km 3, 70010 Valenzano (BA), Italy
² Istituto di Metodologie Inorganiche e dei Plasmi (CNR IMIP), c/o Dept. of Chemistry, Via Orabona 4, 70126 Bari, Italy
³ Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari, Italy

Corresponding author: ^a m.capitelli@area.ba.cnr.it

Received: 9 September 2003
Published online: 15 April 2004

Abstract

Multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy is used for thermometry in H₂ radio-frequency capacitive discharge plasma at low gas temperature of 300-400 K, pressure of 0.4-4 Torr and power of 100 W. Results of the investigation of population densities of rotational levels in the ground electronic state of the hydrogen molecule and measurements of rotational temperature by multiplex H₂ CARS spectroscopy in H₂ radio-frequency capacitive discharge plasma are reported. Computational codes have been realized to determine the rotational and vibrational temperature and to analyze H₂ CARS spectrum for equilibrium and non-equilibrium conditions. To ensure the reliability of the rotational temperature measurements, we also apply method of scanning narrow-band CARS spectroscopy in our investigations.