Neodymium spectra

Neodymium and YAG Lasers. The principle of neodymium and YAG lasers is very similar to that of the ruby laser. Neodymium ions (Nd +) are used in place of Cr + and are often distributed in glass rather than in alumina. The light from the neodymium laser has a wavelength of 1060 nm (1.06 xm) it emits in the infrared region of the electromagnetic spectrum. Yttrium (Y) ions in alumina (A) compose a form of the naturally occurring garnet (G), hence the name, YAG laser. Like the ruby laser, the Nd and YAG lasers operate from three- and four-level excited-state processes. 

Part of the absorption spectrum of an aqueous solution of neodymium(iii) -configuration/ - is shown in Fig. 10-4. The situation shown there is quite typical of the whole of the lanthanoid series i.e. we could have chosen any/" configuration equally well to illustrate the main characteristics of the spectra of lanthanoid complexes. We shall focus on three main features splittings, band widths and absolute excitation frequencies. 

The absolute configuration of C-3 of the chromophore 459 of isopyoverdins was determined to be S from the circular dichroism (CD) spectrum (Cotton effect +242 nm, —290 nm, +358 nm) of 460 obtained from isopyoverdin by acidic hydrolysis <2001T1019>. Diorganotin(iv) complexes with 4//-pyrido[l,2-/z pyrimidin-4-ones 461 <1996AOM47>, complexes of 2-methyl- and 2-methyl-8-nitro-9-hydroxy-4//-pyrido[l,2-tf]pyrimidin-4-ones with Ag(i), Cu(ll), Ni(n), Co(n), and Mn(n) ions <2000RJD587>, 2,4-dimethyl-9-hydroxypyrido[l,2-tf]pyrimidinium perchlorate and its complexes with prasedynium, neodymium, samarium, and europium <2000RJD310> were characterized by UV spectroscopy. 

Figure 1. The near IR absorption spectrum of anhydrous liquid hydrofluoric acid with a few of the many possible IR wavelengths obtainable from a neodymium-doped glass laser superimposed.

The excitation spectrum of neodymium in the doubly doped crystal having 1 per cent chromium and 1.3 per cent neodymium clearly shows chromium bands. From a detailed study of the chromium and neodymium lifetimes, Kiss and Duncan show that energy transfer takes place from the chromium 2E state. This is contrary to the conclusion drawn by Murphy and co-workers on LaA103. 

Spectrum of the Glowing Oxide.—Neodymium oxide is one of the very few solids with a discontinuous spectrum. The spectrum which was known long before neodymium was separated from its fellow element praesodymium, was briefly described by Bunsen1 in 1864, who in the same communication mentions the discovery by Bahr2 of the similarly banded spectrum of erbium oxide. Thus far, however, no thorough-going study seems to have been made of this class of spectrum. 

Figure 13.3 Alpha spectrum of oxidised and reduced plutonium species as separated by the neodymium fluoride technique (oxidised yield tracer 236Pu, reduced yield tracer 242Pu).

Fig. 1. Some useful laser sources in the visible and ultraviolet spectrum. For infrared lasers and also a more complete listing of laser lines see, for example, ref. 1. YAG (II) and YAG (III) signify the second and third harmonics, respectively, of the neodymium YAG laser. KDP, potasium dihydrogen phosphate, and KPB, potassium pentaborate, are frequency doubling crystals.

Trivalent neodymium has f3 configuration and has 41 energy levels. Because of the large number of levels, the absorption spectra of Nd(III) in crystals and solutions contain many bands due to the transitions from ground state 4Ig/2 to the excited levels [142], The assignment of transitions of Nd3+ in the absorption spectrum of Nd3q ion is given in Fig. 8.18. 

Another difference is that the 5/orbitals have a greater spatial extension relative to the Is and Ip orbitals than the 4/orbitals have relative to the 6s and 6p orbitals. The greater spatial extension of the 5/orbitals has been shown experimentally the esr spectrum of UF3 in a CaF2 lattice shows structure attributable to the interaction of fluorine nuclei with the electron spin of the U3+ ion. This implies a small overlap of 5/ orbitals with fluorine and constitutes an / covalent contribution to the ionic bonding. With the neodymium ion a similar effect is not observed. Because they occupy inner orbitals, the 4/ electrons in the lanthanides are not accessible for... 

Laser ablation can be carried out on any material without special sample preparation. The laser beam can be directed onto a defined spot of the sample or moved to different parts to analyse over a defined area. It can be moved in an XYZ plane using a stepper motor and driven in translational motions on which the cell is mounted and with more expensive models can be turned for analysis in other parts of the sample. Lasers can operate in UV, visible, and IR regions of the spectrum and a recent development in laser technology uses neodymium yttrium aluminium garnet (Nd YAG) which gives high repetition rate at a comparatively low power. This method of analysis is suited to bulk analysis of solid materials and the amount of volatility varies from sample to sample. The size of the laser spot can vary from 10 to 250 pm and little or no sample preparation is required. Errors are greatly reduced because of the simple sample preparation, and the fact that no solvents are required reduces interferences. 

NO L 241 0. The fact that twelve oxygen ions are packed around the neodymium ion makes the ion-to-ligand separation unusually large. A glance at the absorption spectrum (18) reveals that most sharp electronic lines do not appear to have noticeable vibronic components the only case where well-defined vibronic lines appear is in group which corresponds to precisely the... 

Figure 3. Photoionization threshold spectra for neodymium. The excitation scheme used in each case is shown on the figure. The scanned laser wavelength calibration is shown at the top of each spectrum. In (a) the 20 300.8 cm 1 level is populated and in (b) the 21 572.6 cm 1 level is populated. The threshold wavelengths indicated yield the same ionization limit value of 5.523 eV. The arrows labeled R. L. indicate the position of the Rydberg convergence limit (3).

The method evolved by Moseley (1887 to 1915) of determining the atomic number enabled chemists to ascertain, as has already been seen, the maximum number of elements that can exist in serial order between any two selected ones. As the atomic numbers of lanthanum and lutecium are 57 and 71, it is clear that it is possible for 13 elements to exist of atomic numbers between these. Now europium was the twelfth to be discovered, but no element corresponding to 61 had been recorded. This should lie between neodymium (60) and samarium (62), and as early as 1902 Bohuslav Brauner had predicted its existence. In 1926 Hopkins, of Illinois, with his collaborators Harris and Yntema, announced the discovery of a new element in the neodymium extracted from monazite sand, the lines of the X-ray spectrum agreeing with those expected for element 61. He called it Illinium. 

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