Double-beam Spectrometer Research Articles

Wide Bandgap InS-based Thin Film: Deposition, Characterization, and Application for SnS Solar Cells

A wide band gap InS-based thin film was deposited onto F-doped SnO2-coated glass by electrochemical deposition from an aqueous solution using a two-step periodic-pulse voltage. The film was characterized optically by a double beam spectrometer, morphologically by a scanning electron microscope. In addition, the composition ratios of the film were measured by Auger electron spectroscopy. Furthermore, the photosensitivity of the film was observed by means of photoelectrochemical measurements, which confirmed that the film showed n-type conduction. Finally, a detailed X-ray photoelectron spectroscopy (XPS) study was performed in order to understand the chemical states of the elements involved in the film composition. The XPS results revealed that the deposited film can be written in the form of InSxOy(OH)z. The film was used along with tin sulfide thin film to fabricate a novel heterojunction.

The intercombination Cd line 326.1 nm and van der Waals potential coefficients [formula omitted] for pure Cd and Cd–inert gas systems

The absorption profiles of the Cd 326.1 nm line for pure Cd and Cd–inert gases (Xe, Kr, Ar, Ne and He) have been carefully studied from the line center to 700 cm −1 in the red wing using a high resolution double beam spectrometer. The density of Cd was about 5.108 × 10 18 atoms cm −3. The temperature dependences of the red wings of these profiles were analysed in the frame work of the Unified Frank Condon (UFC) treatment of pressure broadening of spectral lines developed by Szudy and Baylis. The van der Waals potential coefficient differences Δ C 6 0 and Δ C 6 1 between the ground 10 + state and the two excited states 30 + and 31 were obtained using Kuhn’s law.

Interatomic potentials for the ground state X 10 + and the two excited states 31, 30 + of the intercombination cadmium line 326.1 nm broadened by Kr pressure

The temperature dependence of the Cd line absorption profile at 326.1 nm perturbed by Kr has been carefully studied over a spectral range extending from 800 cm −1 in the blue wing to 1200 cm −1 in the red wing using a high-resolution double-beam spectrometer. The atomic densities of krypton ( N Kr) and cadmium ( N Cd) were (2.015±0.07)×10 19 and (3.62±0.05)×10 18 cm −3, respectively. The temperature dependence of the studied line profile was analyzed in the framework of the quasi-static theory. The van der Waals coefficient differences between the ground 10 + state and the two excited states 30 + and 31 (Δ C 6 0 and Δ C 6 1) were obtained from the near red wing profile using Kuhn's law. The values of Δ C 6 0 and Δ C 6 1 are found to be equal to 37.8±2 and 58.5±3 eV Å 6, respectively. The ground (X 10 +), and the excited ( 31, 30 +) state potentials at the internuclear separations from 3.2 to 6.3 Å were determined. The well depths with their positions for these states are respectively equal to 134±7 cm −1, 3.95±0.2 Å; 72.3±4 cm −1, 4.95±0.3 Å; and 471±12 cm −1, 3.6 Å. The obtained well depths with their allowable errors are in good agreement with the values obtained before for the Cd–Kr system from some theoretical results and molecular beams experiments.

Absorption Spectra of Electronic-Homoeopathic Copies of Homoeopathic Nosodes and Placebo Have Essential Differences

Electronic-homoeopathic copies (EHC), i.e.preparations made by ‘imprinting’ the parent substanceonto water (or other carriers) with the help of M. Rae devices,have gained certain acceptance in some fields of alternativemedicine as homoeopathic nosodes. Objective: Toverify the electronic-homoeopathic copying effect with theuse of absorption spectroscopy. Materials and Methods: Ina double-blind randomized procedure 7 homoeopathicnosodes and a blank placebo were ‘imprinted’ onto ampouleswith saline solution by means of a ‘simulator’ apparatusby Metabolics Ltd (Wiltshire, UK). There were 63 ampoulesof the EHC (9 of each nosode) and 27 ampoules ofthe placebo (3 groups). The absorption spectra of the preparationswere determined by a UV-2101 PC (Shimadzu,Kyoto, Japan) double-beam spectrometer in the wave band800-600 nm at an interval of 0.5 nm. The values of opticaldensity - log (1/transmission coefficient) - were written. Results:The absorption spectra of 3 EHC of the 7 homoeopathicnosodes investigated showed regions marked by statisticallysignificant differences (p < 0.05 for 2 adjacentwavelengths) in the band of 800-700 nm in 2 (as a minimum)out of 3 independent placebo groups. When comparedin independent groups of placebo, the spectral regions- for which the significant differences between theEHC and the placebo were evident - are close to each other(in the range of 0.5-7.0 nm). Conclusion: The result obtainedsupports the existence of an electronic-homoeopathic copyingeffect.

Biosensing Using Porous Silicon Double-Layer Interferometers: Reflective Interferometric Fourier Transform Spectroscopy

A simple, chip-based implementation of a double-beam interferometer that can separate biomolecules based on size and that can compensate for changes in matrix composition is introduced. The interferometric biosensor uses a double-layer of porous Si comprised of a top layer with large pores and a bottom layer with smaller pores. The structure is shown to provide an on-chip reference channel analogous to a double-beam spectrometer, but where the reference and sample compartments are stacked one on top of the other. The reflectivity spectrum of this structure displays a complicated interference pattern whose individual components can be resolved by fitting of the reflectivity data to a simple interference model or by fast Fourier transform (FFT). Shifts of the FFT peaks indicate biomolecule penetration into the different layers. The small molecule, sucrose, penetrates into both porous Si layers, whereas the large protein, bovine serum albumin (BSA), only enters the large pores. BSA can be detected even in a large (100-fold by mass) excess of sucrose from the FFT spectrum. Detection can be accomplished either by computing the weighted difference in the frequencies of two peaks or by computing the ratio of the intensities of two peaks in the FFT spectrum.

Structural and optical characterization of WO3 thin films for gas sensor applications

The structure, chemical composition, and optical properties of tungsten trioxide thin films grown by pulsed laser deposition were investigated. An ultraviolet KrF* excimer laser (λ=248nm, τFWHM≅20ns, ν=2Hz) was used for irradiation of tungsten trioxide targets in oxygen atmosphere. Our research focused on the effect of the ambient gas pressure and substrate temperature on the chemical composition, crystalline status, and optical properties of the obtained thin films. To this end, the films were studied by x-ray diffractometry Raman spectroscopy, and energy dispersive x-ray spectroscopy. Optical transmittance measurements were performed with a double beam spectrometer within the 400–1200nm range. The films deposited at oxygen pressure values higher than 10Pa and substrate temperatures above 300°C consist of crystalline tungsten trioxide. Their average transmittance in the visible-infrared spectral region reaches about 85% appropriate for the envisaged applications.

Interaction potentials of Cd–Ne from temperature dependent of intercombination Cd line [formula omitted

The absorption profile and the temperature dependence of the Cd line at 326.1 nm perturbed by Ne at a density of about 1.13×10 19 atoms cm −3 have been carefully studied over a spectral range extending from 600 cm −1 in the blue wing to 700 cm −1 in the red wing using a high-resolution double-beam spectrometer. Interatomic potentials for Cd–Ne in the ground electronic state 10 + as well as the exited ( 30 + and 31 ) states have been deduced from the spectrum. The van der Waals coefficient differences between the ground 10 + state and the two exited states 30 + and 31 (ΔC 6 0 and ΔC 6 1) are obtained from the near red wing profile using Kuhn's law. The values of ΔC 6 0 and ΔC 6 1 are found to be equal to 23.5±2 and 39.3±3 eV A ̊ 6 , respectively. The interatomic potentials parameters (well depths ε (cm −1) and their positions R m (Å) for the ground 10 + and the exited ( 30 + and 31 ) states are found to be ( 41.4±3, 4.1±0.2 ), ( 82.5±4, 3.7±0.2 ) and ( 18.03±2, 4.25±0.3 ), respectively. The obtained well depths with their allowable errors are in good agreement with the values obtained before for the Cd–Ne system from the molecular beams experiments.

Laser-based double beam absorption detection for aggregation immunoassays using gold nanoparticles

A laser-based double beam absorption detection system for aggregation immunoassays has been developed. The assay was based on the aggregation of gold nanoparticles that are coated with protein antigens in the presence of their corresponding antibodies. The aggregation of the gold nanoparticles results in an absorption change that is monitored at 635 nm using the double beam spectrometer. The noise level of the spectrometer is 1x10(-6)arbitrary units. This corresponds to a tenfold improvement in comparison to commercial absorption detectors and is comparable with previously reported more complicated laser-based absorption spectrometers. The dye Nile-Blue-A was used to test the analytical performance of the system. A limit of detection of 3x10(-8 )M Nile-Blue-A was observed. The relative standard deviation between consecutive measurements was lower than 1.5%. The system is suitable for field applications of aggregation-based immunoassays.

Photoacoustic powder spectra of Ni(II) and Co(II) complexes with aromatic amine N-oxide ligands

A photoacoustic double-beam powder spectrometer that works with lock-in technique implemented as software in a personal computer is described. The influence of mechanical vibrations have been removed by applying the added signal from two microphones placed face to face. The spectra of six Ni(II) and three Co(II) complexes with aromatic N-oxide ligands have been presented and the value of Dq has been compared with values determined with known spectra.

Optical properties of zinc oxynitride thin films

Optical properties of zinc oxynitride (Zn x O y N z ) films are investigated. Zn x N y O z films are deposited onto glass substrates from a ZnO target in N 2–Ar mixtures by reactive rf magnetron sputtering. Structure and chemical bonding states are studied by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. Transmission spectra are measured with a double beam spectrometer. Absorption coefficients are calculated from the transmission spectra with film thickness, and their dependence on photon energy is examined to determine optical band gap ( E g). E g decreases from 3.26 to 2.30 eV with increasing nitrogen concentration in the films. Zn x N y O z is a promising optically functional material that can act in the visible range.

Silver-halide optical fiber for infrared absorption spectroscopy: optically pumped intersubband transitions in quantum-well structures

A silver-halide infrared optical fiber is used in a double-beam spectrometer, demonstrating the ability to guide small infrared signals efficiently. We show that a fractional transmission change of less than 1% is easily measured. Use of the fiber may obviate the necessity for the unfriendly optics currently used in spectrometry systems to probe remote sample zones. As a specific example, we were able to guide with high efficiency an infrared signal to and from a sample that was mounted in a cryostat. Using this setup, we measured the photoinduced absorption due to the e1 ? e2 intersubband transition in a GaAs-GaAlAs multiple quantum-well structure.

Interaction potentials of CdXe from temperature dependent absorption spectra

Abstract The absorption profile and the temperature dependence of the Cd line at 326.1 nm perturbed by Xe at a density of about 1 × 1019 atoms cm−3 have been carefully studied over a spectral range extending from 750 cm−1 in the blue wing to 1400 cm−1 in the red wing using a high resolution double beam spectrometer. Interatomic potentials for CdXe in the ground electronic state 1O+ as well as the exited (3O+ and 31) states have been deduced from the spectrum. The van der Waals coefficient differences ΔC06 and ΔC16 are also obtained. The well depths for the ground 1O+ and the exited (3O+ and 31) states are found to be 192±18, 988±41 and 152±15 cm−1 respectively. The position of the ground state potential well minimum is deduced using the combination rule of Kong and Chakrabarty. The obtained well depth with their allowable errors are in good agreement with the values obtained before for the CdXe system from other experimental methods.

Some effects of 5 eV photons on defects in SiO 2

The effects of 5 eV photons on the optical absorption bands and paramagnetic centers produced by a prior γ-ray irradiation of type III and IV silicas have been measured. Silica samples obtained from two commercial sources were irradiated with 137Cs γ-rays to a dose of ∼10 8 R at an ambient temperature of ∼35°C. The samples were then exposed to 5 eV photons supplied by a pulsed KrF excimer laser. The samples were exposed to pulses from 100 to 11 500 with 150 mJ per pulse per cm −2. Sample temperatures during exposure were <40°C. Optical absorption spectra were measured with a double beam spectrometer in the 1–6 eV range at a temperature of 22°C. Electron paramagnetic resonance (EPR) spectra were measured with a homodyne spectrometer at 9.7 GHz, room temperature and 110 K and at various power levels. After 100 pulses, a band with a peak at 5.5 eV was bleached in the spectra of type III samples. No additional bleaching was observed after 1500 pulses. After 11 500 pulses, a decrease in absorption at 5.8 eV was observed. In the EPR spectra, the E′ center concentration increased by a factor of 1.8 and the concentration of the non-bridging oxygen centers (NBOHCs) did not change after 100 pulses. No additional changes were observed after 1500 pulses. After 11 500 pulses, a decrease of the order of 69% in the E′ center concentration and a decrease of the order of 26% in the NBOHCs was observed. In the spectra of the type IV samples, a band with a peak at ∼4.85 eV was bleached by the first 100 pulses and no additional changes were observed up to 1500 pulses. A band with a peak at ∼5.8 eV decreased with exposure to 11 500 pulses. The E′ center concentration increased by a factor of 1.5 after 100 pulses, did not change after 1500 pulses and decreased by 84% after 11 500 pulses. The peroxy radical molecule ion concentration decreased to below detectability after 800 pulses and a new paramagnetic state grew with increasing number of pulses up to 1500 pulses, after which no additional increase was observed. No oxygen-related center was detected for any exposure in the type III samples. It is concluded that there are at least three bands absorbing at ∼5.8 eV, the E′ center, the E″ center and another band. The 4.8 absorption bleached by 5 eV photons is attributed to the peroxy radical. The absorption at ∼5.5 eV bleached by 5 eV photons is not attributed to any of the paramagnetic states.

Survey on spectral infrared and optical properties of building glasses and panes

In order to judge the energy performance of windows we have measured the spectral transmittance and reflectance of many commercial glazings with two double-beam spectrometers in the wavelength range between 200 nm and 45 μm. From these spectra we have calculated the relevant data of single and multiple glazings with respect to solar and thermal radiation.

Optical investigations of silica aerogels

This paper presents data on the scattering behaviour of base-catalyzed silica aerogels at a wavelength of 633 nm. Scattering from the bulk, which is nearly isotropic, and scattering from the surface, which is strongly forward peaked, were detected. The former can be influenced by changing the processing pH value and the density, but the latter has not been controllable in a systematic way. The mass specific extinction for aerogels as a function of density, thickness and wavelength was measured, using a double beam spectrometer.

Elimination of dispersive line broadening due to a second-axis crystal with an (n, –n,n) diffraction spectrometer

A triple-axis double-beam X-ray spectrometer has been used for high-precision differential lattice-parameter measurements of perfect Si and Ge crystals. When two Ge crystals (the standard and the sample) were mounted on the second axis and two Si crystals (the monochromator and the analyzer, respectively) were on the first and third axes, the second-axis rocking curve was wide because of significant dispersion effects. The third-axis rocking-curve width was instead much smaller and equal to the convolution of the Darwin widths of the monochromator and of the analyzer. The two Ge crystals acted as mirrors and did not contribute to the width of the third-axis rocking curve. This finding is explained by means of the Du Mond diagrams.

Measurement with a double-beam spectrometer of strengths and half-widths of 2 ν2 and 3 ν2- ν2 OCS lines

A double-beam diode laser spectrometer is described. It has been used for the measurement of strength and self-broadening parameters for spectral lines of J between J = 0 and J = 69 in the 02 00←00 00 and 03 10←01 10 band of OCS.

Interatomic potentials for the Hg-Xe system from measurements of the temperature-dependent absorption spectrum

The absorption profile and the temperature dependence of the Hg resonance line at 253.7 nm perturbed by Xe at a density of about 1*1019 atoms/cm3 have been carefully studied with a high-resolution double beam spectrometer. Interatomic potentials for Hg-Xe in the ground electronic state 1O+ as well as the excited state 3O+ in a wide range of separations (from a repulsive wall up to the van der Waals attraction region) have been deduced from the spectrum. Some important results for the excited 31 state, in particular the van der Waals coefficient C6, are also obtained. The ground-state potential with well parameters of epsilon =240+or-10 cm-1 and Rm=4.10+or-0.03 AA, derived experimentally without recourse to any external data, is well reproduced by the Maitland-Smith (1973) ( epsilon , Rm, alpha , beta ) function for alpha =11 and beta =17. The well depth for the 3O+ excimer state is found to be 1450+or-100 cm-1 at a separation of 3 AA. The 1O+ to 3O+ transition moment in the range of separations considered seems to be independent of R.

Gas chromatography in water analysis—I organic profiles of water sources

A method has been developed and used extensively for the routine chromatographic scanning of water sources for trace organic compounds. The method involves solvent extraction of the water with dichloromethane, followed by analysis of the concentrated extract by gas chromatography on a glass SCOT capillary column with flame ionisation detection to yield a water profile. Over 600 extracts from rivers, canals, reservoirs and various stages of water treatment, collected between January 1979 and October 1980 as part of a potability study, were examined. The profiles were quantified using n-paraffin standards and a computerised data system. Components were detected at levels as low as 0.01 μg 1 −1 in the water samples. A Kratos MS-30 double-beam mass spectrometer equipped with a DS-50 data system was used in conjunction with gas chromatography to identify chemical types in over 60 of the organic extracts. Components were generally identified at levels as low as 0.1 μg 1 −1 in the water samples. Many components did not give molecular ions and reference spectra were generally unavailable. In such cases, accurate mass measurement using the double-beam technique, which allowed the calculation of atomic compositions for fragment and molecular ions, was particularly valuable.

Tunable Diode Laser Spectrophotometry: Measurement of Liquid Water Absorption Coefficients

A very accurate measurement of the absorption coefficient of liquid water using a tunable diode laser double beam spectrometer is presented. The water absorption coefficient is 123 ± 1.8 cm−1 at 2590 cm−1 obtained by nonlinear least squares fitting to an exact transmittance formula including the effect of multiple reflections at all four window surfaces, using only the nominal values of the refractive indices of water and window of ZnSe.