Open AccessA diagnosis of gas-phase processes in a high pressure DC CH4/H2 plasma
Author(s) -
Shijian Zheng,
Fang Ding,
Xiangyu Xie,
Tang Zhong-Liang,
Yichuan Zhang,
Huan Li,
Yang Kuan,
Xiaodong Zhu
Publication year - 2013
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.62.165204
Subject(s) - plasma , materials science , cathode , methane , emission spectrum , spectral line , atomic physics , anode , torr , plasma diagnostics , analytical chemistry (journal) , excitation temperature , spectroscopy , electrode , chemistry , physics , organic chemistry , quantum mechanics , astronomy , chromatography , thermodynamics
In this work, gas phase processes in a high pressure (100 Torr) DC hydrocarbon plasma are investigated in situ by optical emission spectroscopy and mass spectroscopy. In the high pressure plasma, optical emission characteristics of glow layers are obviously different. C2, CH dominated band spectra and discrete spectra are distinctively observed in the positive column, whereas the emission intensity is found to decrease in the anode region. In the cathode region, a large number of complicated spectra are detected, which indicates the intensive interaction between the cathode and plasma under high pressure induces complicated atomic and molecular processes. With the the increase of pressure, electron excitation temperature decreases while gas rotational temperature goes up. High methane concentration causes increases in C2, C2H2 and C2H4 but a reduction in C2H6. Those suggest that the effect of gas temperature on gas phase process is significantly enhanced under high pressure.