Rotational and vibrational temperatures of hydrogen nonequilibrium plasmas from Fulcher band emission spectra

Abstract

A roto-vibrational resolved corona model is discussed for the simulation of the Fulcher spectrum in Hydrogen low pressure discharges. The model allows to derive H2 rotational and vibrational temperatures from the analysis of emission spectra in the [600:640] nm range. The model is applied to the analysis of emission spectra collected at the SPIDER negative ion source. Results are presented for different values of the applied power to the plasma, pressure, and for different regions of the plasma, thus providing a characterization of the plasma with respect to the internal temperatures of the molecular component.

Optical emission spectroscopy study in CO2 methanation with plasma

“…35,36) Table I shows the spectroscopic constants of CO(B) and CO(A) used in this study. 32) E e is the minimum electronic energy (cm −1 ), ω e is the vibrational constant in the first term (cm −1 ), and ω e χ e is the vibrational constant of the second term (cm −1 ). The vibrational excitation energy E(v) is expressed as follows using the vibrational constant and vibrational level v;…”

“…OES was performed to estimate the excited species generated by electron impact. [22][23][24][25][26][27][28][29][30][31][32] The light from the whole plasma area is focused using a lens. The lens is placed on the upper side of the reactor, and the focused light was guided to the spectrometer with an optical fiber.…”

“…Then, CO(B) is de-excited to the lower level species CO(A) emission. In addition, in the spectrum, the peaks between 600 and 640 nm are called the Fulcher band, and are produced by the emission species arising from H 2 as represented by the following equation; [30][31][32] H d H x h . 6…”

“…In addition, OES is a useful method for estimating the vibrational temperature. 25,[30][31][32] The vibrational excitation state is often represented by a parameter referred to as the vibrational temperature, which is calculated based on the assumption that the distribution of the vibration excitation state follows the Boltzmann distribution. Plasma-based CO 2 recycling and decomposition technologies are attracting more attention, and more studies aim to elucidate the behavior of vibrationally excited species by OES.…”

Use of electrical measurements for non-invasive estimation of plasma electron density in the inductively coupled SPIDER ion source

“…Atomic and molecular temperatures are given from spectroscopy measurements, as well as γ [22], so that the average background gas density n H2 can be derived. The estimations of the molecular temperatures come from the recent estimations from OES [23]. It is about 500 ± 100 K at 0.3 Pa, for RF power 20-50 kW (per driver) and varies from 450 to 650 K (±100 K) at 50 kW RF power (per driver), for the gas pressure range 0.2-0.6 Pa [23].…”