Figure, emission spectrum

Fig. 7.3. Upper figure Emission spectrum of Jupiter in the far infrared two diffuse, dark fringes are seen at the H2 Sb(0) and Sb(l) rotational transition frequencies, caused by collision-induced absorption in the upper, cool regions. The lower figure presents an enlarged portion which shows the dimer structures near the So(0) transition frequency [150].

Figure Bl.4.3. (a) A schematic illustration of the THz emission spectrum of a dense molecular cloud core at 30 K and the atmospheric transmission from ground and airborne altitudes (adapted, with pennission, from [17]). (b) The results of 345 GHz molecular line surveys of tlu-ee cores in the W3 molecular cloud the graphics at left depict tire evolutionary state of the dense cores inferred from the molecular line data [21],...

In an emission spectrum a fixed wavelength is used to excite the molecules, and the intensity of emitted radiation is monitored as a function of wavelength. Although a molecule has only a single excitation spectrum, it has two emission spectra, one for fluorescence and one for phosphorescence. The corresponding emission spectra for the hypothetical system in Figure 10.43 are shown in Figure 10.44. 

Whereas the emission spectrum of the hydrogen atom shows only one series, the Balmer series (see Figure 1.1), in the visible region the alkali metals show at least three. The spectra can be excited in a discharge lamp containing a sample of the appropriate metal. One series was called the principal series because it could also be observed in absorption through a column of the vapour. The other two were called sharp and diffuse because of their general appearance. A part of a fourth series, called the fundamental series, can sometimes be observed. 

Section 6.13.2 and illustrated in Figure 6.5. The possible inaccuracies of the method were made clear and it was stressed that these are reduced by obtaining term values near to the dissociation limit. Whether this can be done depends very much on the relative dispositions of the various potential curves in a particular molecule and whether electronic transitions between them are allowed. How many ground state vibrational term values can be obtained from an emission spectrum is determined by the Franck-Condon principle. If r c r" then progressions in emission are very short and few term values result but if r is very different from r", as in the A U — system of carbon monoxide discussed in Section 7.2.5.4, long progressions are observed in emission and a more accurate value of Dq can be obtained. 

Figure 8.29 X-ray fluorescence transitions forming (a) a K emission spectrum and (b) an L emission spectrum. The energy levels are not drawn to scale...

Figure 8.30 K emission spectrum of tin. The ] and P2 lines are at 0.491 A and 0.426 A, respectively. (Reproduced, with permission, from Jenkins, R., An Introduction to X-ray Spectrometry, p. 22, Hey den, London, 1976)...

Figure 10-8. Emission spectra of a free standing film of a blend system consisting of 0.9% MEH-PPV in polystyrene with ca. I011 cm 3 TiOj-particlcs. The nanoparlicles act as optical scattering centers. The emission spectrum is depicted for two different excitation pulse energies. Optical excitation was accomplished with laser pulses of duration I Ons and wavelength 532 nm (according to Ref. 171).

An example of the usefulness of x-ray emission spectrography for qualitative trace analysis is shown in Figure 7-1, which contains a chart recording made in the authors laboratory of the emission spectrum from a genuine bank note. 

Figure 2. The fluorescence intensity of PuF Cg) excited at 1064 nm is shown as a function of the energy of the emitted photons. The spectral bandpass and intensity uncertainty are indicated. To within experimental error, the same emission spectrum is found when 532 nm excitation is used.

Figure 3. Emission spectrum of 10-100 fm surface sulfhydryl derlvatlzed glass beads following treatment with aqueous 1.0 x 10 M SnCl and ethanollc 5.0 x 10 M flavonol.

Figure 4. Emission spectrum of Pseudomonas 244 following treatment with aqueous 2.0 x 10" M n-butyltri-chlorotin and 50% ethanolic 1.0 x 10" M flavonol.

Figure 1. Average corrected emission spectrum (- -) and excitation spectrum (- -) for quinine sulfate In 0.1 mol/L HC10 obtained during round-robin test with ten laboratories coefficient of variation at each wavelength (-t).

Figures 3a-f show the emission and excitation spectra for all six humic fractions. The excitation and emission maxima are listed in Table III along with the maxima of the phase-resolved emission spectra. In each case the emission spectrum was scanned with the excitation maximum wavelength held constant, and the excitation spectrum was scanned with the emission maximum wavelength held constant. Several interesting features are noted. The two humic samples ( Figures 3a,b) each have two excitation maxima and it appears that a double peak has been merged into the emission scan as evidenced by the shoulder on the high energy side of the emission peak. Similarly it seems evident that the exaggerated shoulders in the emission spectra of all the fractions point to the inclusion of two emission peaks in each spectrum. This evidence suggests the presence of two chromophores in each humic fraction.

Humic materials fractionated on the basis of hydrophobicity and proton affinity continue to exhibit two fluorophores as discussed in the section "Exciation-Emission Spectra. Strong evidence to establish the existence of at least two chromophores is seen in the phase-resolved spectra. These spectra are shown in Figures 4 a-f. They consist of the phase-resolved emission spectrum of each of the two fluorophores plotted separately and the normal emission spectrum of the humic fraction. If the nulling out of one fluorophore is exact then the sum of the two separate phase resolved spectra should be additive to equal the normal spectrum. In these figures the normal emission spectrum was measured separately from the two phase resolved emision spectra. The phase resolved spectra were then superimposed onto the scan of the normal emission spectrum. 

Figure 4. Phase-resolved plots of the six humic fractions superimposed on the normal emission scan for each fraction. The emission spectrum of the first fluorophore was suppressed and a scan was made of the second fluorophore then the second fluorophore was suppressed and an emission scan was made of the first fluorophore. Fractions hydrophobic humic weak (a) and strong (b) acids.

Figure 6. Time-resolved Fourier transform emission spectrum in the CO2 asymmetric stretch region from the HCCO + 02 reaction. Only signal from is observed. The fit to the data is...

Figure 5.3 Room-temperature emission spectrum of [Au (PPh3)3] in acetonitrile. Reproduced with permission from [14]. Copyright (1992) American Chemical Society.

Figure 5.16 Excitation (left, emission monitored at 500 nm) and emission (right) spectra of [Au2(dcpm)2]X2 (X = CF3S03 and T), with kex at 280 nm, in degassed acetonitrile at room temperature, and emission spectrum of [Au2(dcpm)2](SCN)2, with at 280nm, in EtOH/MeOH (1 4 v/v) at 77 K. Reproduced with permission from [6b]. Copyright (2001) Wiley-VCH.

Figure 8.19 Changes in the emission spectrum of 26a (n=12) upon heating. Spectra shown at 25 (highest intensity), 35,45, 55,...

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