Spectrometer tests with rare earth salts.

 

Reference spectra recorded on a Shimadzu 2100 UV-visible spectrometer. The samples are made of solutions of some rare earth nitrates in a 1cm path length cell. Rare earth salts with their incomplete filling of 4f orbitals have multibands spectra in the visible range and are thus used for the calibration of monochromators.

A few drops of the Pr, Nd and Sm salts have been evaporated on a microscope object slide and spectra were recorded with the microscope spectrometer described previously. The resolution is not as good as the Shimadzu instrument because I'm using a large entrance slit   ( 2 mm ) to increase the light throughput of the system. Nevertheless, the resolution is sufficient for the purpose of the examination of  mineral spectra. The peaks appear at the same wavelength positions after calibration.

The resolution can be improved with a 0.5 mm entrance slit and a higher sampling frequency: 1 point per nm instead of 1point per 2 nm in the previous figure.

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