The Experts below are selected from a list of 13773 Experts worldwide ranked by ideXlab platform

Robert Osiander - One of the best experts on this subject based on the ideXlab platform.

  • wideband Terahertz Spectroscopy of explosives
    Chemical Physics Letters, 2007
    Co-Authors: Michael J. Fitch, Xuemei Zheng, L.m. Hayden, M R Leahyhoppa, Robert Osiander
    Abstract:

    Time-domain Terahertz Spectroscopy (TDTS) has been shown to be a promising tool in detection of explosives and explosive related compounds. To date, TDTS for many explosives has been limited to spectral regions <3 THz. With recent improvements in emitters and sensors of THz radiation, we report the THz absorption spectra over an extended frequency band from 0.5 to 6 THz for four explosives: RDX (1,3,5-trinitroperhydro-1,3,5-triazine), HMX (1,3,5,7-tetranitroperhydro-1,3,5,7-tetrazocine), PETN (pentaerythritol tetranitrate), and TNT (2,4,6-trinitrotoluene). New distinctive spectral features are shown in these materials between 3 and 6 THz. These data may aide in the spectral identification of these explosives.

  • Wideband Terahertz Spectroscopy of explosives
    Chemical Physics Letters, 2006
    Co-Authors: M.r. Leahy-hoppa, Michael J. Fitch, Xuemei Zheng, L.m. Hayden, Robert Osiander
    Abstract:

    Time-domain Terahertz Spectroscopy (TDTS) has been shown to be a promising tool in detection of explosives and explosive related compounds. To date, TDTS for many explosives has been limited to spectral regions

Erik Brundermann - One of the best experts on this subject based on the ideXlab platform.

  • Terahertz Spectroscopy: System and Sensitivity Considerations
    IEEE Transactions on Terahertz Science and Technology, 2011
    Co-Authors: H-w Hubers, M.f. Kimmitt, N. Hiromoto, Erik Brundermann
    Abstract:

    Terahertz Spectroscopy is a backbone method in many areas of research. We have analyzed typically employed THz Spectroscopy systems and their sensitivity in a general comparative approach. Recent progress to reduce the data acquisition time by frequency multiplexing using a spectrometer with a THz quantum cascade laser is described. The performance of a spectrometer using a pulsed Ge THz laser with a few μs long integration time and recent progress to modulate the laser current within such a short pulse are presented. We also investigate the origin of random errors in intensity spectra of a THz TDS with the goal to identify common error sources in TDS systems to allow reduction of the total measurement time.

  • solute induced retardation of water dynamics probed directly by Terahertz Spectroscopy
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: U Heugen, Gerhard Schwaab, Erik Brundermann, Matthias Heyden, Xin Yu, David M Leitner, Martina Havenith
    Abstract:

    The dynamics of water surrounding a solute is of fundamental importance in chemistry and biology. The properties of water molecules near the surface of a bio-molecule have been the subject of numerous, sometimes controversial experimental and theoretical studies, with some suggesting the existence of rather rigid water structures around carbohydrates and proteins [Pal, S. K., Peon, J., Bagchi, B. & Zewail A. H. (2002) J. Phys. Chem. B 106, 12376–12395]. Hydrogen bond rearrangement in water occurs on the picosecond time scale, so relevant experiments must access these times. Here, we show that Terahertz Spectroscopy can directly investigate hydration layers. By a precise measurement of absorption coefficients between 2.3 THz and 2.9 THz we could determine the size and the characteristics of the hydration shell. The hydration layer around a carbohydrate (lactose) is determined to extend to 5.13 ± 0.24 A from the surface corresponding to ≈123 water molecules beyond the first solvation shell. Accompanying molecular modeling calculations support this result and provide a microscopic visualization. Terahertz Spectroscopy is shown to probe the collective modes in the water network. The observed increase of the Terahertz absorption of the water in the hydration layer is explained in terms of coherent oscillations of the hydration water and solute. Simulations also reveal a slowing down of the hydrogen bond rearrangement dynamics for water molecules near lactose, which occur on the picosecond time scale. The present study demonstrates that Terahertz Spectroscopy is a sensitive tool to detect solute-induced changes in the water network.

M R Leahyhoppa - One of the best experts on this subject based on the ideXlab platform.

  • wideband Terahertz Spectroscopy of explosives
    Chemical Physics Letters, 2007
    Co-Authors: Michael J. Fitch, Xuemei Zheng, L.m. Hayden, M R Leahyhoppa, Robert Osiander
    Abstract:

    Time-domain Terahertz Spectroscopy (TDTS) has been shown to be a promising tool in detection of explosives and explosive related compounds. To date, TDTS for many explosives has been limited to spectral regions <3 THz. With recent improvements in emitters and sensors of THz radiation, we report the THz absorption spectra over an extended frequency band from 0.5 to 6 THz for four explosives: RDX (1,3,5-trinitroperhydro-1,3,5-triazine), HMX (1,3,5,7-tetranitroperhydro-1,3,5,7-tetrazocine), PETN (pentaerythritol tetranitrate), and TNT (2,4,6-trinitrotoluene). New distinctive spectral features are shown in these materials between 3 and 6 THz. These data may aide in the spectral identification of these explosives.

Martin Koch - One of the best experts on this subject based on the ideXlab platform.

Villy Sundström - One of the best experts on this subject based on the ideXlab platform.