Strontium-88, excitation

Holmuhamedov EL, Teplova VV, Chukhlova EA, et al. 1995. Strontium excitability of the inner mitochondrial membrane Regenerative strontium-induced strontium release. Biochem Mol Biol hit 36(l) 39-49. 

C07-0112. The bright red color of highway safety flares comes from strontium ions in salts such as Sr(N03)2 and SrC03. Burning a flare produces strontium ions in excited states, which emit red photons at 606 nm and at several wavelengths between 636 and 688 nm. Calculate the frequency and energy (kJ/mol) of emissions at 606, 636, and 688 nm. 

A road flare contains a salt of strontium to give a red colour to the flame. Write the electron configuration of the strontium ion, with an electron in the least excited energy state. 

In general, excited atoms emit spectral lines, i.e. the radiation lies in very narrow wavelength ranges of width 10 to 10 nm. In practice, atomic resonance lines from species, such as strontium in a red star, contribute little to the visual effect since the emission falls in the short wavelength part of the spectrum (this line may be observed in a Bunsen burner flame at 461 nm). 

The strong strontium (red), barium (green) and copper (green) colours in a flame have also been attributed to a process known as chemiluminescence whereby excited SrOH, BaOH and CuOH molecules are formed directly in the excited state in the flame and are not dependant on ground-state concentrations. 

An interpretation of the absorption spectrum in the low-excitation phase has been made by Williams (1987), based on line identifications of scandium, strontium,... 

Of course, predictable differences between He(2 5) and He(23S) occur regarding the polarization of Penning ions and electrons caused by total spin conservation. The fact that a component of spin angular momentum is conserved in Pgl has been demonstrated by the observation of the transfer of spin polarization from optically pumped He(23S) atoms to the Penning ions of cadmium, zinc, and strontium.72 The polarization was detected by measuring the polarization of the light emitted from the excited 2Ds/2 ions in 2Ds/2- 2D2/2 transitions. If a component of spin angular momentum is conserved, we may write the Pgl process as... 

The Srs(P04)3Cl crystals are hexagonal needles with lattice parameters ah = 9.953 A. and ch = 7.194 A. The needle axis corresponds to the crystallographic c axis. The europium(II) doped sample is a phosphor, readily excitable with electrons, x-rays, and both short and long ultraviolet light. It emits in the blue with a peak at 445 nm. Crystals of strontium chloride vanadate(V) are orthorhombic platelets with lattice constants a = 7.43 A., b = 11.36 A., and c = 6.54 A., with the b axis corresponding to the thin dimension of the flakes. Strontium chloride vanadate(V) is a self-activated phosphor giving broadband emission with a peak at 423 nm. when excited with 2537-A. radiation. All compounds are insulators, with resistivities >1012 ft-cm. 

There is much interest in this superconductor for two reasons. Measurements of the effect of pressure on the material indicate that the onset transition temperature increases to 147 K when the pressure is raised to 230000 times atmospheric pressure (23.5giga Pascal). The result excited many researchers because pressure on a material can be created chemically by replacing some fraction of an ion by a similar ion of smaller radius. The obvious choice in this case was to replace the larger barium with smaller strontium. This had worked with the lanthanum compound discussed earlier. Unfortunately nature is not always so predictable. Replacement of barium by strontium reduced Tc to 127 K instead of increasing it beyond 133 K. The other reason for the interest in this material seems much more important. Resistance measurements in dc magnetic fields have shown... 

The energies of excitation of zinc, cadmium and mercury are greater than those of calcium, strontium and barium, where there are no d electrons in the penultimate electronic... 

Figure 24 shows the excitation spectra at 4.2 K of the Eu " emission of strontium hromoborate (82). In the spectrum the presence of 4/ 5d excitation bands can be observed. The lower energetic band, located between some 330 and 400 nm, depending on the host lattice, shows a well-resolved structure due to the splitting of the 4/ configuration in the 4/ 5d excited state. This has been discussed elsewhere (83). The features we are interested in at present are the dips in the excitation spectrum around 320 nm and 295 nm. The positions of these dips coincide with the positions of the Ij and Dj excited states within the... 

Lattice dynamics in bulk perovskite oxide ferroelectrics has been investigated for several decades using neutron scattering [71-77], far infrared spectroscopy [78-83], and Raman scattering. Raman spectroscopy is one of the most powerful analytical techniques for studying the lattice vibrations and other elementary excitations in solids providing important information about the stmcture, composition, strain, defects, and phase transitions. This technique was successfully applied to many ferroelectric materials, such as bulk perovskite oxides barium titanate (BaTiOs), strontium titanate (SrTiOs), lead titanate (PbTiOs) [84-88], and others. 

The general viability of low-temperature flame photometry depends on two factors. First, the alkali and alkaline earth metals of analytical interest (sodium, potassium, lithium, cesium, rubidium, magnesium, calcium, strontium, and barium) reach their excited states at relatively lower temperatures than do most other elements. Second, the emission wavelengths offer enough resolution such that optical filtering can be accomplished at a relatively low cost. 

Edwards C, Lorkovic H, Weber A. 1966. The effect of the replacement of calcium by strontium on excitation-concentration coupling in frog skeletal muscle. J Physiol 186 295-306. 

Sodium salts, such as sodium chloride, furnish sodium ions, which, when excited, produce yellow light (a wavelength of 589 nm). Red colors arise from salts of strontium, which emit several shades of red corresponding to wavelengths in the 600-to 700-nm region of the visible spectrum. Copper salts produce blue radiation, because copper emits in the 400- to 500-nm spectral region. 

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