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Hi! The example questions: Pyroxene group mineral diopside crystallizes in the monoclinic structure. The chemical formula, structural data, space group site positions, and list of all possible Raman modes are provided below. Find number and symmetry of Raman active modes for this mineral. Which elements in the chemical formula will contribute to vibrations represented as Raman active bands in the spectra The provided information is in the images. So, I’m not sure whether the mention of monoclinic structure impacts anything, and whether rounding is ok – e.g. if y for Si were 0.49, could I consider that close enough to 1/2 to count it or it just remains y as far as the site positions are concerned? It looks to me like Si, Mg and Ca would contribute with 9 modes of symmetry, but I don’t know what the Z=4, a, b, c, etc are for or if I use them here. I see numbers and my brain freezes. I also have no idea what Ag and Au even mean but it seems that the u ones are inactive, though I’m not clear why. another example reads That it says cubic, given the information provided, I don’t know if that changes anything. Thanks very much! submitted by /u/gneissdinoguy to r/Spectroscopy |