Density function theory (DFT) calculated infrared absorption spectra for nitrosamines.

Absorption spectra within the infrared (IR) range of frequencies for nitrosamines in water are calculated using density function theory (DFT). Calculated in this study, are the IR spectra of C2H6N2O, C4H10N2O, C6H14N2O, C4H8N2O, C3H8N2O, and C8H18N2O. DFT calculated absorption spectra corresponding to vibration excited states of these molecules in continuous water background can be correlated with additional information obtained from laboratory measurements. The DFT software Gaussian was used for the calculations of excited states presented here. This case study provides proof of concept, viz., that such DFT calculated spectra can be used for their practical detection in environmental samples. Thus, DFT calculated spectra may be used to construct templates, for spectral-feature comparison, and thus detection of spectral-signature features associated with target materials.

Issues concerning spectral analysis of water samples for monitoring and treatment of public water resources.

Experimental measurements conducted in the laboratory, involving hyperspectral analysis of water samples taken from public water resources, have motivated a re-evaluation of issues concerning the potential application of this type of analysis for water monitoring, treatment and evaluation prior to filtration. One issue concerns hyperspectral monitoring of contaminants with respect to types and relative concentrations. This implies a need to better understand the statistical profiles of water contaminants in terms of spatial-temporal distributions of electromagnetic absorption spectra ranging from the ultraviolet to infrared, which are associated with specific water resources. This issue also implies the need to establish correlations between hyperspectral signatures and types of contaminants to be found within specific water resources. Another issue concerns the use of absorption spectra to determine changes in chemical and physical characteristics of contaminants after application of water treatments, in order to determine levels of toxicity with respect to the environment. This paper presents a prototype spectral analysis showing various aspects relevant to water monitoring and discusses the use of basic theory for the interpretation of spectral features associated with water contaminants, as well as discussing inverse analysis of hyperspectral measurements.

Prototype reflectivity analyses of hydrogen storage levels in single-walled carbon nanotubes.

A prototype case study is presented that examines the level of hydrogen content in H-SWNTs using the Surface Plasmon Resonance technique. The damping effect and the angular shift in the resonance minimum of an SWNT-gold interface due to the presence of hydrogen is analyzed using a parametric model, which is based on the concept of an effective permittivity. The new approach provides for a non-invasive analysis of the level of hydrogen content in H-SWNTs and is potentially extendable to other carbon-based hydrogen storage materials.