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Since the first confirmation of quantum monodromy in NCNCS (B. P. Winnewisser et al., Report No. TH07 in 60th International Symposium on Molecular Spectroscopy, Columbus, OH, (2005) and B. P. Winnewisser et al., Phys. Rev. Lett., 2005, 95, 243002) we have continued to explore its implications for the quantum structure of molecules. To confirm quantum monodromy bending-vibrational + axial-rotational quantum energy level information is needed. This was not directly available from the pure a-type rotational transitions available in 2005. The confirmation of quantum monodromy therefore had to be based on the fitting of the Generalised SemiRigid Bender (GSRB) model to the experimental rotational data. The GSRB is a physically motivated model and was able to extract the required information based on the changes of the rotational energy level structure upon excitation of the bending vibration and of the axial rotation. These results were, in some sense, predictions. Our goal here was to obtain a fully experimental and unambigous confirmation of quantum monodromy in NCNCS. This involved a series of experimental campaigns at the Canadian Light Source (CLS) synchrotron. To coax the required information out of the masses of spectral data that had been obtained a variety of techniques had to be used. The result is that we can now confirm, without recourse to a theoretical model, the existence of quantum monodromy in the ν7 bending mode of NCNCS. As a side benefit we also confirm the power of the GSRB model to extract the required information from the previously available data. The predictions previously provided by the GSRB were surprisingly accurate. Only a slight augmentation of the model was required to allow us to refit it including the new data, while maintaining the quality of the fitting for that data previously available. We also present a very basic introduction to the idea of monodromy and to how the GSRB was used. [ABSTRACT FROM AUTHOR]

The United States Army Research Laboratory (ARL) has been applying standoff laser-induced breakdown spectroscopy (LIBS) to hazardous material detection and determination. We describe several standoff systems that have been developed […]

A technique being evaluated for standoff explosives detection is laser-induced breakdown spectroscopy (LIBS). LIBS is a real-time sensor technology that uses components that can be configured into a ruggedized standoff instrument. The U.S. Army Research Laboratory has been coupling standoff LIBS spectra with chemometrics for several years now in order to discriminate between explosives and nonexplosives. We have investigated the use of partial least squares discriminant analysis (PLS-DA) for explosives detection. We have extended our study of PLS-DA to more complex sample types, including binary mixtures, different types of explosives, and samples not included in the model. We demonstrate the importance of building the PLS-DA model by iteratively testing it against sample test sets. Independent test sets are used to test the robustness of the final model. OCIS codes: 020.0020, 140.3440, 280.0280, 300.6210, 300.6365.

Laser-induced breakdown spectroscopy (LIBS) was used to discern between two biological agent surrogates (Bacillus atrophaeus and ovalbumin) and potential interferent compounds (mold spores, humic acid, house dust, and Arizona road dust). Multiple linear regression and neural network analysis models were constructed by using B. atrophaeus and ovalbumin spectra, and limits of detection were calculated. Classification of the agent surrogates' LIBS spectra was attempted by using a neural network model. False negative rates of 0% were observed for B. atrophaeus (100 colony forming units) spore spectra with the neural network model used for classification. OCIS codes: 140.3440, 300.6365, 280.3420.

The provenance of gem stones has been of interest to geologists, gemologists, archeologists, and historians for centuries. Laser induced breakdown spectroscopy (LIBS) provides a minimally destructive tool for recording the rich chemical signatures of gem beryls (aquamarine, goshenite, heliodor, and morganite). Broadband LIBS spectra of 39 beryl ([Be.sub.3][Al.sub.2][Si.sub.6][O.sub.18]) specimens from 11 pegmatite mines in New Hampshire, Connecticut, and Maine (USA) are used to assess the potential of using principal component analysis of LIBS spectra to determine specimen provenance. Using this technique, beryls from the three beryl-bearing zones in the Palermo #1 pegmatite (New Hampshire) can be recognized. However, the compositional variation within this single mine is comparable to that in beryls from all three states. Thus, a very large database with detailed location metadata will be required to routinely determine gem beryl provenance. OCIS codes: 140.3440, 160.0160.

The performance of a man-portable laser induced breakdown spectrometer was evaluated for the detection of biological powders on indoor office surfaces and wipe materials. Identification of pure unknown powders was performed by comparing against a library of spectra containing biological agent surrogates and confusant materials, such as dusts, diesel soot, natural and artificial sweeteners, and drink powders, using linear correlation analysis. Simple models constructed using a second technique, partial least squares discriminant analysis, successfully identified Bacillus subtilis (BG) spores on wipe materials and office surfaces. Furthermore, these models were able to identify BG on materials not used in the training of the model. OCIS codes: 280.1415, 300.6210, 300.6365.

The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory have developed a terahertz (THz)-band imaging system performance model for detection and identification of concealed weaponry. The MATLAB-based model accounts for the effects of all critical sensor and display components and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination. The model is based on recent U.S. Army NVESD sensor performance modeling technology that couples system design parameters to observer-sensor field performance by using the acquire methodology for weapon identification performance predictions. This THz model has been developed in support of the Defense Advanced Research Project Agencies' Terahertz Imaging Focal-Plane Technology (TIFT) program and is currently being used to guide the design and development of a 0.650 THz active-passive imaging system. This paper will describe the THz model in detail, provide and discuss initial modeling results for a prototype THz imaging system, and outline plans to calibrate and validate the model through human perception testing. OCIS codes: 110.6795, 220.4830, 110.4100, 110.3000.

A number of energetic materials and explosives have been studied by laser-induced breakdown spectroscopy (LIBS). They include black powder, neat explosives such as TNT, PETN, HMX, and RDX (in various forms), propellants such as M43 and JA2, and military explosives such as C4 and LX-14. Each of these materials gives a unique spectrum, and generally the spectra are reproducible shot to shot. We observed that the laser-produced microplasma did not initiate any of the energetic materials studied. Extensive studies of black powder and its ingredients by use of a reference spectral library have demonstrated excellent accuracy for unknown identification. Finally, we observed that these nitrogen-and oxygen-rich materials yield LIBS spectra in air that have correspondingly different O:N peak ratios compared with air. This difference can help in the detection and identification of such energetic materials. OCIS codes: 140.3440, 300.630, 300.6210.

The fast-scan submillimeter spectroscopy technique (FASSST) is an instrument that provides great speed and improved analytical and detection capabilities. FASSST is based on the last part of the electromagnetic spectrum, the submillimeter, that is electronically tunable sources of high spectral brightness and spectral purity. Aside from its sensitivity, the FASSST instrument is also faster and less complex than other submillimeter systems.

A study calculating the pressure broadening in 183 and 380 GHz transitions of water vapor was conducted using hydrogen and helium as broadening agents in a temperature region of 80-600K. Results indicate that a simple power law is sufficient to obtain the values and that there is a deviation in low temperatures. The behavior of both helium and hydrogen as broadening agents are presented.