Composition, variations and excitation of the auroral luminescence spectra.

  • 51 Pages
  • 1.85 MB
  • English
J. Griegs boktr., I kommisjon hos Aschehoug, Oslo , Bergen
Auroras., Spectrum anal
SeriesGeofysiske publikasjoner,, v. 19, no. 9
LC ClassificationsQC801 .N67 vol. 19, no. 9
The Physical Object
Pagination51 p.
ID Numbers
Open LibraryOL213685M
LC Control Numbera 58000859

Luminescence spectroscopy of single crystals is a technique that often leads to spectra with well-resolved vibronic structure. 25,99– In the vast majority of coordination compounds, luminescence is observed only from the lowest-energy excited state and often the polarizations are less distinct than in absorption spectra.

An illustrative example is the spectrum of the square planar Pd(SCN. The photoluminescence (PL) spectra of the nano-CdS containing glass nanocomposites exhibiting green luminescence under nm diode laser excitation (power W) is shown in Figure a.

Highly intense peak is at nm and a broad peak is in the range nm. The excitation wavelength was nm and the source used was a diode laser. It is important to understand the origin of the graphs and curves displaying the excitation and emission spectra for a given fluorochrome.

In order to determine the emission spectrum of a particular fluorochrome, the wavelength of maximum absorption (usually the same as the excitation maximum) is determined and the fluorochrome is excited at.

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For the spectra of anthracene drawn in Figurethat would correspond to an excitation wavelength of nm and emission wavelength of nm. The one exception is if the S 0 -S 1 transition is the maximum on both spectra, which would mean having the excitation and emission monochromators set to the same wavelength.

Luminescence - Luminescence - Luminescence excitation: Most of the energy liberated in chemical reactions, especially oxidation reactions, is in the form of heat.

In some reactions, however, part of the energy is used to excite electrons to higher energy states, and, for fluorescent molecules, chemiluminescence results. Studies indicate that chemiluminescence is a universal phenomenon.

shows the Luminescence spectra for the syn-thetic alexandrite sample measured at several tempera-tures. Figure 1(a) evidences the lines R, and. Figure 1(b), lines S. Below room temperature, the luminescence spectra is dominated by the R lines of individual Cr ions and the S lines, originated from exchange-coupled pairs of chromium ions [11].

Otmar M. ten Kate, J. Ruud van Ommen, H. (Bert) Hintzen, Influence of composition and structure on the thermal quenching of the 5d–4f emission of Eu 2+ doped M–Si–N (M = alkali, alkaline earth, rare earth) nitridosilicates, Journal of Materials Chemistry C, /C9TCD, ().

Abstract. The luminescence and excitation spectra of [(CH 3) 4] 2 UO 2 F 4, M 3 UO 2 F 5 (M = K and Rb) and Cs 2 SnCl 6:UO 2 Cl have been recorded at temperatures down to 10 K.

The excitation spectrum of [(CH 3) 4] 2 UO 2 F 4 is unique because the electronic origin is located at the lowest energy reported for any uranyl compound.

The analysis of the excitation spectrum is consistent with a. Auroral Colors and Spectra. When the aurora is faint, it appears white to the unaided eye. As its brightness increases, color vision starts to work, and the characteristic pale.

Description Composition, variations and excitation of the auroral luminescence spectra. FB2

The luminescence and excitation spectra of the perdeuterated and the protonated ruthenocene have been carefully investigated. The electronic origins are at 21 cm −1 and at 21 cm −1 for the perdeuterated and protonated crystals, respectively.

The two observed luminescence progressions in the metal‐ring stretch a ’ 1 (D 5h notation) in the perdeuterated crystal are separated by.

fluorescence – excitation, emission and 3D – and luminescence scans, the Infinite M provides great scanning flexibility in all detection modes, providing a great tool for academic research and assay development.

Impact of integration times on luminescence emission spectra 0   1. Fused silicas which show the increased absorption in the uv and the lack of the OH absorption at μ are considered “reduced.” Exact information on method of manufacture is highly proprietary but the similarity of such silicas from various manufacturers is striking.

The absorption and luminescence spectra of neodymium in mixed scandates of yttrium and gadolinium are investigated, especially the nature and the structure of arising activator centres.

It is shown that the scandium ion may partially replace the crystallographic sites that are characteristic of RE ions. The luminescence spectra of Mn 3+ ions in minerals and synthetic materials have been rarely measured. A strong Jahn–Teller effect introduces various channels for non-radiative relaxation and the quenching of manganese lumi-nescence.

The intensive Mn 3+ luminescence at room- and low temperatures was measured only by Kück et al. The Γ 7 (2 T 2g, t 3 2g)→Γ 8 (4 A 2g) luminescence spectra, emissive life-times, excitation spectra and Γ 8 (4 A 2g)→Γ 6 (2 T 1g, t 3 2g), Γ 7 Γ 8 (2 T 2g, t 3 2g) absorption spectra of ReCl 2– 6 in A 2 SnCl 6 (A = K, Rb, Cs) and K 2 PtCl 6 have been measured between 4 and K.

The absorption and luminescence spectra of each transition are dominated by three vibronic origins due. UC PL Spectra (a) UC Luminescence spectra of glasses under an excitation of nm i) No AgCl, ii) mol% AgCl, iii) mol% AgCl, iv) mol% AgCl (b) Ag concentration dependent emission intensity.

Maximum amplification for the green and red bands occur at mol% Ag (Glass C). Absorption, fluorescence, and excitation spectra of ammonium bromide which has a CsCl‐like structure at room temperature, activated by various amounts of thallium are investigated at room temperature in order to ascertain the nature of the electronic states involved in the luminescence.

Photoluminescence spectra of high-quality bulk AlN crystals are reported. In addition to the expected linear luminescence features like free excitons and donor-bound excitons, nonlinear processes like biexcitons and the exciton-exciton scattering band are seen for higher excitation densities.

For temperatures above ≈K the electron-hole plasma becomes clearly visible in the spectra. Spectra 1) Excitation Spectrum – fluorescence or phosphorescence intensity (at fixed λ) as a function of excitation λ or absorption λ 2) Fluorescence Emission Spectrum-fluorescence emission intensity vs.

λ for a fixed excitation λ (= absorption λ, max.) 3) Phosphorescence Emission Spectrum – phosphorescence emission intensity vs. The difference between an excitation spectrum and absorption spectrum.

In the excitation spectrum you do a scan on a specific-emission wavelength monitored, e.g. Eu3+ at nm, and the absorption. An experiment is described utilizing a novel luminescent organogel.

The gel's unique cross-linking structure has been used by other scientists as a template for the synthesis of nanosize magnetic materials. This cross-discipline laboratory was designed for chemistry majors taking physical chemistry or instrumental analysis during their third or fourth year.

In this paper the luminescence spectra of Y 6 UO 12, Li 4 UO 5, Li 2 UO 4, and MgUO 4 are discussed. Emission and excitation spectra and the decay time of the luminescence have been measured at low temperatures (T spectra of the investigated uranates is analysed.

1 Introduction and Background. Auroral events suggest signatures of acceleration processes in the Auroral Acceleration Region, Magnetosphere‐Ionosphere (MI) coupling region, and magnetotail (Birn et al., ).Ground‐based imaging of auroral intensities, spectra, and structures are used to examine these acceleration processes and increase our understanding of the complex physics in each of.

afterglow spectra recorded at the excitation temperatures are in Fig. If the temperature of excitation is lowered, the intensity of luminescence decreases and for excitation at 90 K it is reduced by factor 3 relative to intensity for excitation at RT.

The normalized spectra coincide well (inset in Fig. 3) indicating the peak position. Rees M.H. () Auroral Excitation and Energy Dissipation.

In: Carovillano R.L., Forbes J.M. (eds) Solar-Terrestrial Physics. Astrophysics and Space Science Library (A Series of Books on the Recent Developments of Space Science and of General Geophysics and Astrophysics Published in Connection with the Journal Space Science Reviews), vol 2. DEFINITION OF LUMINESCENCE AND PARAMETERS USED IN ANALYSIS Types of luminescence The various types of molecular luminescence observed can be classified by (a) the mode of excitation to the excited state capable of emission and (b), the type of.

Single-ion luminescence due to Mn 2+ and donor-acceptor pair luminescence due to (Cu, Al), (Ag, Al) and (Au, Al) centered in hexagonal ZnS have been investigated at 75 K with a major focus on exciton structures in the excitation spectra.

Appearance of exciton peaks in Mn 2+ luminescence excitation spectra indicates that the isoelectronic Mn center can bind a free exciton.

Details Composition, variations and excitation of the auroral luminescence spectra. EPUB

Electron impact excitation of auroral spectral features in the visible and ultraviolet are computed by solving the complete electron transport equation. Excitation rates are given for several bands of N 2 (A³Σ, B³Π, W³Δ, a¹Π, C³Π) and of N 2 +, for bands of O 2 (a¹Δ, b¹Σ) and of O 2 +, and for several states of O (¹D, ¹S, 5 S.

Luminescence Spectra and Vibrations in Crystal Lattices bedding, e.g., in ruby. Where the distortion of the lattice is greater, the spectra are more diffuse. Out of the many naturally occurring stones such as the ruby, sapphire, red spinet, etc., which emit the red fluorescence of the. tion by a HeCd laser The resulting luminescence was dispersed by a grating spectrometer and detected using a photomultiplier tube Be is proposed to form a shallow acceptor in GaN and is thus critical to device development and performance From analysis of the PL spectra, a shallow level appears consistently following an annealing procedure.

The excitation-intensity dependences of photoluminescence (PL) and optically detected magnetic resonance were measured before and after prolonged light exposure at 2K.Abstract. Auroral spectroscopy provided the first tool for remotely sensing the compositions and dynamics of the high-latitude ionosphere.

InBalmer discovered that the visible hydrogen spectrum consists of a series of discrete lines whose wavelengths follow a simple mathematical pattern, which ranks among the first steps toward developing this tool. The fine structure of luminescence spectra of azurin.

Burstein EA, Permyakov EA, Yashin VA, Burkhanov SA, Finazzi Agro A. The spectra of azurin absorption, fluorescence, phosphorescence and fluorescence excitation have been measured in aqueous solutions at ordinary and liquid nitrogen temperatures.