Iodine Atomic Lines Research Articles

Monomolecular decomposition of C3F7I and CF3I: Theory meets experiment

For the first time, the rate constant of the thermal monomolecular decomposition of n-C3F7I in Ar was measured directly using the technique of atomic resonance absorption spectroscopy on a resonant line of iodine atom. Experiments were conducted behind the incident and reflected shock waves in a broad range of thermodynamic parameters (T = 800–1200 K and P = 0.6–8.3 bar). Experimental data were found to conform reasonably to the results of the Rice–Ramsperger–Kassel–Marcus theory master equation modeling based on the results of quantum chemical calculations. The obtained low- and high-pressure limiting rate constants for n-C3F7I and CF3I dissociation in Ar were reported. Third body efficiencies for Kr were also evaluated.

Influence of the iodine vapor pressure on the output characteristics of a UV low-pressure gas-discharge lamp

The influence of the iodine vapor pressure on the output characteristics of a UV lamp pumped by a longitudinal glow discharge is studied. The lamp is filled with a helium-iodine mixture to a pressure of 100–1500 Pa. In the spectral range 320–360 nm, the I2(D′ → A′) band with a peak at 342 nm prevails, while in the bactericidal range, iodine atomic lines at 183.0 and 206.2 nm dominate. The power of the UV lamp is optimized according to the iodine vapor pressure and working mixture composition by numerical simulation.

Comparison Study of Subsonic and Transonic Mixing in a Multi-Kw Grid-Nozzle Supersonic Chemical Oxygen Iodine Laser

The present study compares the laser medium properties for subsonic and transonic iodine injection schemes of a multi-kW grid-nozzle supersonic chemical oxygen iodine laser (COIL). Two supersonic nozzles of similar geometry having subsonic or transonic iodine injectors were investigated in the present study. Small signal gain (SSG) and internal cavity temperature (ICT) were experimentally measured as a function of the iodine flow rate and coordinate in the direction of the gas flow. Dissociated fraction of iodine F and the number N of O2(1Δ) molecules consumed for the dissociation of one iodine molecule were estimated by an analytical method, utilizing SSG and ICT as input parameters. Both gain and temperature were measured by diode laser spectroscopy. Pressure broadening of the spectroscopic line of iodine atom was taken into account when calculating the gas temperature in the cavity.

A Broadband Excimer-Halogen Emitter Utilizing Xenon Bromide and Iodide

The results are given of an investigation of the output characteristics of an electric-discharge excimer-halogen UV emitter utilizing a Xe/Br2/J2 mixture. A longitudinal glow discharge with an interelectrode spacing of 50 cm and inside diameter of the discharge tube of 1.4 cm is ignited at the working mixture pressure of ≥1 kPa and power input to the plasma of 10–350 W. A study is performed of the current-voltage characteristics of the discharge, plasma radiation spectra in the 190–350 nm range, and distributions of the brightness of radiation of molecules as a function of the pumping conditions, as well as of pressure and partial composition of the gas mixture. It is demonstrated that the plasma of the discharge being investigated is a source of broadband UV radiation in a system of bands of 253 nm XeJ, 282 nm XeBr, and 292–310 nm Br2*, which are joined by the radiation of resonance line of iodine atom with λ = 206 nm. The total power of UV radiation of plasma increases linearly with the electrical power of the glow discharge.

Fluorescence lifetime studies of no a 2Σ +(ν = 5, N = 9), B 2Π [formula omitted](ν = 8, J = 8.5), C wΠ [formula omitted](ν = 1, J = 8.5), D 2Σ + (ν = 0, N = 5) and D 2Σ +(ν = 1, N = 9)

Fluorescence decay profiles of NO excited levels slightly above the dissociation limit have been measured by a single-photon counting technique with nanosecond pulse excitation using an iodine flash lamp. Three iodine atomic lines in the vicinity of 180 nm are found to bring NO molecules into the levels A 2Σ +(ν = 5, N = 9), B 2 2Π 3 2 (ν = 8, J = 8.5), C 2Π 3 2 (ν = 1, J = 8.5), D 2Σ +(ν = 0, N = 5) and D 2Σ +(ν = 1, N = 9). Extrapolated zero-pressure lifetimes for single rotational levels are obtained, except for the C state where only a lifetime of ⩽0.4 ns was obtained. Self-quenching rate constants are also determined under higher-pressure conditions. Helium was found to quench the NO A 2Σ +(ν′ = 5) fluorescence very efficiently.

Fluorescence of NO A 2Σ +(υ′= 5), B 2Π(υ′= 8) and C 2Π(υ′= 1) excited by iodine atomic lines

NO was irradiated by a low-pressure iodine discharge lamp which induced fluorescence from excited NO molecules. From analysis of fluorescence spectra it was found that the A 2Σ +(υ′ = 5), C 2Π(υ′ = 1) and B 2Π(υ′ = 8) states were excited by iodine atomic lines at 179.9, 183.0 and 187.6 nm, respectively. By comparing undispersed fluorescence intensities of NO with an without N 2, the predissociation of A 2Σ +(υ′ = 5) was estimated to be much weaker than that of B 2Π(υ′ = 8) or C 2Π(υ′ = 1).