Resolution of the spectrograph

The spectral interval AA transmitted by the spectrograph should be smaller than 8v in order to avoid the overlap of different orders. This means that the spectral resolution of the spectrograph... 

Correction of simple laser-induced broadening effects may not be necessary if the resolution of the spectrograph is three or four times lower than the laser bandwidth. If this is not the case and no other steps to correct for the laser profile are attempted, the long-term stability of any model will depend greatly on the consistency of the laser profile. Because some lasers exhibit unusual profiles in an inconsistent manner, repeatability is... 

Spectra in emission. The conclusion of his musing was that there was no good reason for neglecting atomic absorption spectra [147], Obviously, Walsh also had to consider the question of the proper radiation source for recording atomic absorption spectra, and he came to the conclusion that a resolution of approximately 2 pm would be required if a continuum source was used. This was far beyond the capabilities of the best spectrometer available in his laboratory at that time, and he concluded that One of the main difficulties is due to the fact that the relations between absorption and concentration depend on the resolution of the spectrograph. .. [147]. This realization led him to conclude that the measurement of atomic absorption requires line radiation sources with the sharpest possible emission lines. The task of the monochromator is then merely to separate the line used for the measurement from all the other lines emitted by the source. The high-resolution demand for atomic absorption measurements is thus provided by the line source. 

The spatial resolution of the Raman microprobe is about an order of magnitude better than that obtainable using an infrared microscope. Measurement times, typically of a few seconds, are the same as for other Raman spectrographs. To avoid burning samples, low (5—50-mW) power lasers are employed. 

For the discrete bands in this region, the absorption intensities are somewhat greater in Vigroux s results than in the authors . This is undoubtedly due to the better dispersion and resolution of his spectrograph. However, the differences are small and do not cause a serious discrepancy. 

Elements not increasing in concentration with ash content are generally those with (a) organic affinities (Ca, Mg, Sr, Ba) (b) sulfide affinities (Fe, Zn) (c) carbonate affinities (Ca, Mn, Mg) or (d) sulfate affinities (Ba, Sr, Ca). Sulfides, carbonates, and sulfates are generally epigenetic phases, that is, they precipitate in the cleats and fractures subsequent to coalification. Presence of epigenetic phases affects element concentration more than ash content. The concentrations of Zr and Nb would be expected to increase with ash content, because these elements are usually associated with the detrital compounds of coal. The reason that this behavior is not apparent in Table II may be the poor resolution of the technique (emission spectrographic analysis) used to obtain the data. 

---