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Low-frequency (2.72-3.70 Hz) relaxation oscillations at 100 mTorr at higher absorbed power were observed from time-varying optical emission of the main discharge chamber and the periphery. We interpret the low frequency oscillations using an electromagnetic model of the slot impedance with parallel connection variational peripheral capacitance, coupled to a circuit analysis of the system including the matching network. The model results are in general agreement with the experimental observations, and indicate a variety of behaviours dependent on the matching conditions. 相似文献
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VIDISHA RAI HEINZ-PETER LIEBERMAN ROBERT J. BUENKER ALEKSEY B. ALEKSEYEV REINHARD ZELLNER 《Molecular physics》2013,111(6):809-820
Ab initio multireference configuration interaction calculations including spin-orbit coupling have been carried out for the first time for valence electronic states of the TeX (X = Cl, Br, I) radicals and compared with the results for the isovalent TeF and IO systems obtained earlier at a similar level of theoretical treatment. The calculated spectroscopic constants are in good agreement with experimental data in the rare cases when the latter are available. It is shown that the X2 II(σ2π4π?3) ground state bonding becomes consistently weaker down the TeX group (calc. De, = 25480cm?1 for TeF, 12 100cm?1 for Tel) due to the more covalent character of bonding in the heavier radicals. The first excited state, A 4Σ? (π?→ σ?), is calculated to be bound in all systems. It is split into Ω 1/2 and 3/2 components, with regular ordering in the Franck-Condon region, opposite to that of the ground X2II state. For larger internuclear distances, the A1 4Σ? 1/2 state undergoes an avoided crossing with X2 2II1/2, which causes a shoulder in the X2 potential curve and also leads to a crossing between the A1, and A2 curves and large distinctions in their vibrational frequencies. The π? → σ? B2Σ?, C2δ, and 1 2Σ+ states are calculated to lie next in energy. They are all bound in the lightest of the TeX radicals, TeF, but successively lose their bonding character down the group. In contrast to oxygen monohalides, the 22II(σ2π3 π?4) state has a repulsive potential curve. Electric dipole transition moments and radiative lifetimes have also been calculated for the low lying bound states in all systems. Most of them are found to be quite weak. The A1,2 → X1,2 spectra are dominated by parallel contributions, with the A2 → X1 being the strongest one. The T values for this transition are quite similar and lie in the 17–30 μs range. Radiative lifetime values for the B → X1,2 transitions demonstrate very irregular behaviour for various, TeX radicals, due to strong admixture of A4Σ? character to the X1,2 states near the B2Σ? potential minimum. The A1,2 4Σ? 1/2,3/2 and B2Σ? 1/2 states of TeX (X = Cl, Br, I) still await their experimental observation. 相似文献
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Instability Parameters of Optical Oscillation Frequency in Plasma Central Discharge and Periphery Region 下载免费PDF全文
We have observed relaxation oscillations in a capacitive discharge in Ar gas, connected to a peripheral ground chamber. The plasma oscillations observed from time-varying optical emission from the main discharge chamber show, for example, a high frequency (75.37kHz) relaxation oscillation, at lOOmTorr and 8 W absorbed power, and a low frequency (2.72Hz) relaxation oscillation, lOO mTorr and 325 W absorbed power. Time-varying optical emission intensity and plasma density are also detected with a Langmuir probe. The theoretical result agrees well with experiments. 相似文献
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