Upper part: second derivative calculation (dotted line) of the Raman CH
region (solid line). The band positions are indicated with a star under the second
derivative.(a) Mastic; (b) archeological copal (black line: internal sampling, gray
line: surface sampling). Lower part: fitting results of the Raman CH massif.
Experimental spectrum: black dotted line, calculated spectrum: solid red line,
decomposition bands: solid gray line.(c) Mastic; (d) archeological copal (internal
sampling). It turns out that the decomposition bands are precisely at the positions
that were given by the second derivative. (For interpretation of the references to
color in this figure legend, the reader is referred to the web version of this article.)