The micro-Raman spectroscopy was used to identify manganese oxides, pyrolusite, manganite and cryptomelane in archaeological sites in northern Atacama Desert, Chile. The present micro-Raman data allow us to compare and expand the origins of raw materials used by archaic groups of the Atacama Desert. In the Andean highlands, pyrolusite and manganite were identified while in the coastal lowlands manganite and cryptomelane were found. The present results complement the data obtained from the lithic materials and rock art painting analyses pointing to a better understanding of the daily life of ancient populations and minerals use in this region.

Resonance Raman spectra, a normal coordinate analysis, and calculation of excited-state bond lengths and angles of bis[hydrotris(3,5-dimethyl-1-pyrazolyl)borato]copper(II) are reported. Raman spectra are obtained in resonance with a ligand field state and the lowest ligand-to-metal charge transfer (LMCT) excited state. A normal coordinate analysis is carried out using Raman and IR frequencies and resonance Raman intensities to assist in the assignment of the symmetric modes. Potential energy distributions (PED) and force constants are reported. The individual bond length changes are calculated by using the resonance Raman intensities and the PED. Bond length and angle changes throughout the entire three-dimensional skeleton are reported. The signs of the bond length changes in the pyrazolyl borate ring are interpreted in conjunction with the results of a molecular orbital calculation. The NN bond length decreases by 0.02 Å, the CN bond lengths increase by 0.05 and 0.08 Å, the Cu−N bond increases by 0.10 Å and the NBN angle decreases by 2° in the LMCT excited state.

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Polyethylenes, homo and copolymers obtained via metallocene catalyst, were synthesized and used to study the effect of comonomer size and content in the main linear backbone polymer on its degradation. Homoethylene metallocene polymer, ethylene-1-hexene and ethylene-1-octadecene metallocene copolymer films were characterized and analyzed during their aging in a forced draft oven at 60 ºC for one year. The polymers were characterized before and after ageing using GPC, DSC, FTIR, and tensile tests in order to detect changes in chemical structure, size, and molecular weight distribution as well as to quantify the effect of time over their useful life. As a qualitative reference parameter, the carbonyl index, the ratio of the infrared absorbance of the CO stretching band at 1715 cm -1 and the absorbance of a reference band at 718 cm -1 , was determined. Results showed that kinetic thermooxidation is related to comonomer size and content in the main backbone polymer. As comonomer size decreases or comonomer content increases, degradation rate increases. This can be observed through the scission factor (S) and carbonyl index (CI) graphs of each material which show a slope increasing related to the autocatalytic rate of oxidation.