Emission Spectra Of Particles Research Articles

ON THE FORMATION OF EXCITED YTTRIUM PARTICLES UNDER ION BOMBARDMENT OF YTTRIUM AND YTTRIUM ALUMINUM GARNET

Emission spectra of excited yttrium particles ejected from the surface of the yttrium metal and yttrium aluminum garnet (YAG) at Ar+ ions are studied. The efficiency of yttrium particles excitation defined from experimental data. The assumption is made that the difference in the excitation efficiency for yttrium atoms and ions is due to the different contribution of processes of formation of the excited atoms or ions ejected from solids at the ion bombardment of garnet and metal.

Identifying laser-induced plasma emission spectra of particles in a gas–solid flow based on the standard deviation of intensity across an emission line

A scheme named the standard deviation method is presented for identifying the spectral data of a gas–solid flow based on laser-induced breakdown spectroscopy.

Comparison of the main parameters of the ion-photon emission of titanium atoms and singly charged ions

The emission spectra of titanium particles (TiI and TiII) sputtered during Ar+-ion bombardment of a titanium surface are investigated. The experimental dependences of the efficiency of Ti atom and ion excitation on the excited-state energy are determined. For the TiI and TiII spectral lines, the spatial distribution of radiation is studied and the kinetic energy of particles flying off the surface is determined. These data are used to make assumptions about processes occurring in the system under consideration.

A wavelength-dispersive instrument for characterizing fluorescence and scattering spectra of individual aerosol particles on a substrate

Abstract. We describe a novel, low-cost instrument to acquire both elastic and inelastic (fluorescent) scattering spectra from individual supermicron-size particles in a multi-particle collection on a microscope slide. The principle of the device is based on a slitless spectroscope that is often employed in astronomy to determine the spectra of individual stars in a star cluster but had not been applied to atmospheric particles. Under excitation, most commonly by either a 405 nm diode laser or a UV light-emitting diode (LED), fluorescence emission spectra of many individual particles can be determined simultaneously. The instrument can also acquire elastic scattering spectra from particles illuminated by a white-light source. The technique also provides the ability to detect and rapidly estimate the number fraction of fluorescent particles that could contaminate a collection of non-fluorescent material, even without analyzing full spectra. Advantages and disadvantages of using black-and-white cameras compared to color cameras are given. The primary motivation for this work has been to develop an inexpensive technique to characterize fluorescent biological aerosol particles, especially particles such as pollen and mold spores that can cause allergies. An example of an iPhone-enabled device is also shown as a means for collecting data on biological aerosols at lower cost or by utilizing citizen scientists for expanded data collection.

SIMLA: Simulating particle dynamics in intense laser and other electromagnetic fields via classical and quantum electrodynamics

We present the Fortran program SIMLA, which is designed for the study of charged particle dynamics in laser and other background fields. The dynamics can be determined classically via the Lorentz force and Landau–Lifshitz equations or, alternatively, via the simulation of photon emission events determined by strong-field quantum-electrodynamics amplitudes and implemented using Monte-Carlo routines. Multiple background fields can be included in the simulation and, where applicable, the propagation direction, field type (plane wave, focussed paraxial, constant crossed, or constant magnetic), and time envelope of each can be independently specified. Program summaryProgram title: SIMLACatalogue identifier: AEWD_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEWD_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 4536No. of bytes in distributed program, including test data, etc.: 38351Distribution format: tar.gzProgramming language: Fortran.Computer: Home and office-spec desktop and laptop machines, networked or stand alone.Operating system: Linux, Mac OS, Windows, with Fortran compiler. Matlab required to exploit full post-processing features.RAM: Varies greatly depending on calculation to be performed.Supplementary material: A SIMLA manual with tutorial type examples is available.Classification: 15.Nature of problem: Calculation of dynamics and emission spectra of charged particles in multiple (intense) laser and other background fields, including effects of classical and quantum radiation reaction.Solution method: Solution of the Landau–Lifshitz equation (or simply Lorentz equation for weak fields), or alternatively, via the simulation of photon emission events determined by strong-field quantum-electrodynamics amplitudes and implemented using Monte-Carlo type routines.Restrictions: As a single particle code, the parameters are restricted to a regime in which pair production does not occur. The program will abort with an explicit error message if such a parameter regime does occur in a given simulation.Additional comments: Classical spectra calculated separately in independent Matlab program ‘spectrum.m’. Manual included with tutorial style examplesRunning time: Varies greatly depending on calculation requested, from seconds to hours.

Fluorescence-based ion-sensing with colloidal particles.

Particle-based fluorescence sensors for the quantification of specific ions can be made by coupling ion-sensitive fluorophores to carrier particles, or by using intrinsically fluorescent particles whose fluorescence properties depend on the concentration of the ions. Despite the advantages of such particle-based sensors for the quantitative detection of ions, such as the possibility to tune the surface chemistry and thus entry portal of the sensor particles to cells, they have also some associated problems. Problems involve for example crosstalk of the ion-sensitive fluorescence read-out with pH, or spectral overlap of the emission spectra of different fluorescent particles in multiplexing formats. Here the benefits of using particle-based fluorescence sensors, their limitations and strategies to overcome these limitations will be described and exemplified with selected examples.

Shape-Controlled Micro/Nanostructures of 9,10-Diphenylanthracene (DPA) and Their Application in Light-Emitting Devices

Two novel shapes of 9,10-diphenylanthracene (DPA) micro/nanostructures: octahedron and sphere together with microrod and nanowire have been synthesized via a surfactant-assisted self-assembling process. These micro/nanostructures have been characterized by UV−vis, fluorescence spectra, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and transmission electron microscope (TEM). Our results indicated that the absorption and emission spectra of as-prepared particles were slightly blue-shift when the shape of DPA particles changed from octahedron to microrod and finally to nanowire. This result could be explained by the different growth directions of DPA micro/nanostructures. To study the relationship between shape and devices’ performance, the heterojunction light emitting diode (LED) devices of quartz/ITO/organic particles/n-SiC/Ti(10 nm)/Au(120 nm) have been prepared. The testing results showed that the different shapes of DPA micro/nanostructures did affect the performance of ...

Risk assessment of TiO 2 photocatalyst by individual micrometer-size particle analysis with on-site combination of SEM-EDX and SR-XANES microscope

Applications of synchrotron radiation X-ray fluorescence (SR-XRF) microscopy combined with scanning electron microscopy (SEM) are reported. Electron beam excited and synchrotron radiation induced X-ray emission spectra of the same yellow sand single particles are reported and compared. The Ti-K edge absorption fine structure of single microparticles of TiO 2 (rutile, anatase, and a photocatalyst aerosol) are recorded by using monochromatic synchrotron radiation of tunable energy. It is shown that the discrimination between rutile and anatase is possible. Based on the single particle speciation, the toxicity of photocatalyst aerosol powder is discussed.

Polymer-supported solution synthesis of blue luminescent BaMgAl 10O 17:Eu 2+ particles

A blue phosphor, europium doped barium magnesium aluminate (BaMgAl 10O 17:Eu 2+) 200–300 nm in size, has been synthesized via a solution phase method using a mixture of metal hydroxide with metal chloride as the precursor source. A water-soluble polymer of high molecular weight was used in the synthesis process. The effects of polymer media and heating treatments on the physical and optical properties such as crystallinity and photoluminescence of particles were investigated. Activation of the luminescence center under a reducing atmosphere has been accomplished concurrently with crystal growth. Photoluminescent (PL) emission spectra of particles centered around 450 nm when using a 254 nm excitation wavelength. The polymer potentially prevents agglomeration and enhances the PL emission of the particles.

Preparation and Characterization of Water-Soluble Jingle-Bell-Shaped Silica-Coated Cadmium Sulfide Nanoparticles

Treatment of surface silanol groups with hydrophilic compounds enabled silica-coated cadmium sulfide (SiO2/CdS) nanoparticles of core−shell morphologies to be dissolved in a water/methanol mixture. Size-selective photoetching of the particles was performed by irradiation with monochromatic light at 458 nm, resulting in a blue shift of its absorption onset because of the decreasing size of the CdS. TEM analyses revealed that the SiO2 shell structure was not shrunken by photoetching and that a void space (ca. 2.3 nm) was formed between the CdS core and the SiO2 shell to give a jingle-bell structure. The emission spectra of photoetched particles showed the development of band-gap emission when cadmium ion (Cd2+) was added and the pH was adjusted to 10, whereas the same treatment of original particles gave no peaks assigned to band-gap emission, indicating that the SiO2 shell was sufficiently porous for small ionic species such as Cd2+ to penetrate through the shell and that the photoetched CdS core incorpora...

Variation of Single Particle Mid-Infrared Emission Spectrum with Particle Size

The emission spectra of single particles of inorganic solids as a function of particle size have been recorded from 6 micro to 11.8 micro. For small optically thin particles, an emission maximum is produced in the reststrahlen region. The emission behavior is dominated by scattering and can be adequately described in terms of Mie absorption efficiency factors. As the particle size is increased, the emission band reverses its polarity, and the spectrum approaches that of a polished plate. The data provide source functions necessary for determining the emission behavior of particulate samples in which temperature gradients exist, such as on the lunar surface. The data are of particular interest for interpreting the spectral behavior of circumstellar silicate particles.