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Title: Raman Spectroscopy, X-ray Diffraction, and Hydrogenation Thermochemistry of N,N,N,N-Tetramethylcyclotriborazane under Pressure

Authors:
; ; ;  [1]
  1. (CIW)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCES
OSTI Identifier:
1140255
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Phys. Chem. C; Journal Volume: 118; Journal Issue: (19) ; 05, 2014
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Potter, Robert G., Somayazulu, Maddury, Cody, George, and Hemley, Russell J. Raman Spectroscopy, X-ray Diffraction, and Hydrogenation Thermochemistry of N,N,N,N-Tetramethylcyclotriborazane under Pressure. United States: N. p., 2014. Web. doi:10.1021/jp410192q.
Potter, Robert G., Somayazulu, Maddury, Cody, George, & Hemley, Russell J. Raman Spectroscopy, X-ray Diffraction, and Hydrogenation Thermochemistry of N,N,N,N-Tetramethylcyclotriborazane under Pressure. United States. doi:10.1021/jp410192q.
Potter, Robert G., Somayazulu, Maddury, Cody, George, and Hemley, Russell J. Wed . "Raman Spectroscopy, X-ray Diffraction, and Hydrogenation Thermochemistry of N,N,N,N-Tetramethylcyclotriborazane under Pressure". United States. doi:10.1021/jp410192q.
@article{osti_1140255,
title = {Raman Spectroscopy, X-ray Diffraction, and Hydrogenation Thermochemistry of N,N,N,N-Tetramethylcyclotriborazane under Pressure},
author = {Potter, Robert G. and Somayazulu, Maddury and Cody, George and Hemley, Russell J.},
abstractNote = {},
doi = {10.1021/jp410192q},
journal = {J. Phys. Chem. C},
number = (19) ; 05, 2014,
volume = 118,
place = {United States},
year = {Wed Aug 20 00:00:00 EDT 2014},
month = {Wed Aug 20 00:00:00 EDT 2014}
}
  • We performed high-pressure Raman scattering and angle-dispersive synchrotron X-ray diffraction measurements on n-heptane at room temperature. It has been found that n-heptane undergoes a liquid to rotator phase III (R{sub III}) transition at 1.2 GPa and then transforms into another rotator phase R{sub IV} at about 3 GPa. As the pressure reaches 7.5 GPa, a transition from an orientationally disordered R{sub IV} phase to an ordered crystalline state starts and is completed around 14.5 GPa. Our results clearly present the high-pressure phase transition sequence (liquid-R{sub III}-R{sub IV}-crystal) of n-heptane, similar to that of normal alkanes.
  • No abstract prepared.
  • High-pressure methods were applied to investigate the structural stability and hydrogen bonding of polar molecules of iodoform by synchrotron radiation X-ray diffraction and Raman spectra measurements, respectively. Up to a pressure of 40 GPa, no phase transitions were observed. The discontinuous frequency shift of the C-H stretching band is believed to be related to the enhancement of the C-H{hor_ellipsis}I weak hydrogen bonds under high pressures. Ab initio calculations were performed, and the results predict the frequency shift of the C-H stretching vibration as C-H{hor_ellipsis}I interacts via hydrogen bonding. The bulk modulus is 17.3 {+-} 0.8 GPa, with a pressure derivativemore » of 5.2.« less
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  • Cubic boron phosphide, BP, has been studied in situ by X-ray diffraction and Raman scattering up to 55 GPa at 300 K in a diamond anvil cell. The bulk modulus of B{sub 0} = 174(2) GPa has been established, which is in excellent agreement with our ab initio calculations. The data on Raman shift as a function of pressure, combined with equation-of-state (EOS) data, allowed us to estimate the Grüneisen parameters of the TO and LO modes of zinc-blende structure, γ{sub G}{sup TO }= 1.26 and γ{sub G}{sup LO }= 1.13, just like in the case of other A{sup III}B{sup V} diamond-like phases, for which γ{sub G}{sup TO }> γ{submore » G}{sup LO }≅ 1. We also established that the pressure dependence of the effective electro-optical constant α is responsible for a strong change in relative intensities of the TO and LO modes from I{sub TO}/I{sub LO} ∼ 0.25 at 0.1 MPa to I{sub TO}/I{sub LO} ∼ 2.5 at 45 GPa, for which we also find excellent agreement between experiment and theory.« less