A Monte Carlo code to get response spectrum of ions for Neutron Depth Profiling

This paper presents a Monte Carlo code to get response spectrum of ions for the Neutron Depth Profiling (NDP) technique called Monte Carlo NDP (MC-NDP) that simulates the behavior of ions transmitted through a sample matrix and generates the energy spectrum for a specified detector. The MC-NDP model is based on the Ziegler–Biersack–Littmark Model, but incorporates the advantages of TRIM and CORTEO. The Impulse Approximation method is used to determine the flight length with the indexical interpolation method rather than the Magic algorithm for the scattering angle between ions and nucleus. This makes MC-NDP more efficient and convenient to simulate entire ion histories by a Monte Carlo approach. MC-NDP’s results agree well with both TRIM results and the experimental data.     

Line intensities of Co2 in the 2.0 micron region

The line intensities of the three δ-δ bands of CO₂ and their associated Π-Π hot bands in the 2.0 υ region have been measured using a combination of long optical paths and low sample pressures with high resolution (0.035 cm^-1). These intensities yield total band strengths of 0.200, 0.969, 0.288, 0.0017, 0.062 and 0.028 cm^-2 atm^-1 at 296 K for the 04⁰1-00⁰0, 12⁰1-00⁰0, 20⁰1-00⁰, 05¹1-01¹0, 13¹1-01¹0 and 21¹1-01 ¹0 bands, respectively. The rotationless dipole moment matrix element and the German-Wallis coefficients are also determined for each band.     

Advancement of light-element neutron depth profiling at the University of Texas

The University of Texas (UT) at Austin has collaborated with the National Institute of Standards and Technology for comparisons of concentration versus depth profiles of samples containing ¹⁰B. Technology sharing from NIST has allowed UT to avoid many initial set backs such that significant advancements in the UT-NDP facility’s experimental and analytical methodology have been achieved. UT has analyzed two samples loaned to them from NIST. The collaborative effort between the two institutions has given the UT-NDP facility the proper tools to begin profiling more advanced samples in hopes of meeting the capabilities set by NIST in the NDP field. The UT-NDP facility was able to profile a borosilicate surface deposit onto silicon such that the concentrations of ¹⁰B at various depths of the deposit were determined and fit well to a Pearson distribution.     

Copper and palladium complexes with N-heterocyclic carbene ligands functionalised with carboxylate groups

The new imidazolium salts functionalised with the trimethylsilyl ester group 1a–c, were easily obtained by quaternisation of alkyl- or aryl-imidazoles with trimethylsilyl bromoacetate. Salt 1a was isolated and fully characterised. It reacted with mesityl copper (Cu₅Mes₅) under trimethylsilyl abstraction to form the complex 2. Methanolysis of 1a–c gave good yields of the carboxylic acid functionalised imidazolium salts 3a–c. Deprotonation of the latter in liquid ammonia led to the zwitterionic imidazolium carboxylates 4a–c. Reaction of 4a with (Cu₅Mes₅) gave solutions from which the insoluble polymeric 5a crystallised slowly. Generation of the carboxylate-functionalised NHC in situ followed by reaction with Pd(OOCCH₃)₂ gave the new complex 6a in which the NHC-carboxylate ligand is chelate bidentate.