No two samples will produce the same Raman spectrum
, making each measurement unique, similar to a fingerprint.
A Raman spectrum
is then automatically acquired from each particle.
energy, and the abscissa of a Raman spectrum
displays shifts rather than
The Raman spectrum
is a molecular fingerprint of the material, and can be used to identify materials, typically by computing the correlation to a spectral library from the sample to a model of known materials.
The typical Raman spectrum
for high crystalline anatase structure should present one A1g band localized close to 520 [cm.sup.-1], two B1g bands localized close to 400 [cm.sup.-1] and also at 520 [cm.sup.-1] in overlapping with A1g band and finally, three Eg bands localized close to 150 [cm.sup.-1], 200 [cm.sup.-1] and 640 [cm.sup.-1], once the B2u vibrational mode is silent.
Deprotonation, degradation, and possible carbonization may occur during Raman spectrum
recording [21, 22].
Measurement of Raman Spectrum
. All Raman spectra in this paper were measured with dispersive Raman microscope of Horiba HP Evolution.
Scardaci et al., "Raman spectrum
of graphene and graphene layers," Physical Review Letters, vol.
Each Raman spectrum
was measured with accumulation of 10 s, and averaged by 3 times.
The PCs were estimated by least-square fitting the first LVs and the sample spectrum, where the fitting coefficients were referred to these "new PCs" of each LV present in each Raman spectrum
of the commercial medicines.
Assume that y is a vector of the Raman spectrum
and z is the fitting vector; both of them are with the length of N elements.
Figure 4 shows the Raman spectrum
of R6G dripped on the surface of a silicon wafer and GO.