Gustav Borstad - Academia.edu (original) (raw)

Papers by Gustav Borstad

Bulletin of the American Physical Society, Mar 13, 2017

Submitted for the MAR17 Meeting of The American Physical Society Spectroscopic and structural stu... more Submitted for the MAR17 Meeting of The American Physical Society Spectroscopic and structural study of LLM-172 under pressure GUSTAV BORSTAD, JENNIFER CIEZAK-JENKINS, U.S. Army Research Laboratory-The properties of energetic materials have been investigated to permit the synthesis and scale-up of novel energetic materials possessing low sensitivity without sacrificing performance. To this end, there have been considerable efforts expended on the preparation of molecular crystals featuring unsaturated heterocycles with energetic functional groups such as LLM-105 and LLM-172 (BNFF-1) 1. This permits the compounds to maintain high densities while controlling their stability and sensitivity. Due to the nature of energetic phenomena, varying pressure (and thus density) is a valuable tool to explore the properties of these materials. We will present data on LLM-172 compressed in diamond anvil cells to 50 GPa and characterized by Raman spectroscopy and synchrotron powder x-ray diffraction. These techniques allow for the exploration of the evolution of the structure and bonding with pressure. In particular, we will examine the changes as the sample approaches the detonation pressure (near 34 GPa) 2 .

Journal of Chemical Physics, May 12, 2017

Bulletin of the American Physical Society, Mar 22, 2011

99164-Binary mixtures of water and hydrogen under pressure are of interest both as fundamental sy... more 99164-Binary mixtures of water and hydrogen under pressure are of interest both as fundamental systems in physics and chemistry and due to their applicability to fuel cells. Their behaviors at extreme pressures and temperatures are also of significance to understanding the interaction of chemical species in the interiors of giant gas planets and other planetary objects. In this talk, we will present high-pressure Raman data of deuterium water mixtures, which provides both kinetic information regarding the proton exchange reactions and the structure of deuterium in the mixtures.

Science Advances, Jan 10, 2020

Carbon-based frameworks composed of sp 3 bonding represent a class of extremely lightweight stron... more Carbon-based frameworks composed of sp 3 bonding represent a class of extremely lightweight strong materials, but only diamond and a handful of other compounds exist despite numerous predictions. Thus, there remains a large gap between the number of plausible structures predicted and those synthesized. We used a chemical design principle based on boron substitution to predict and synthesize a three-dimensional carbon-boron framework in a host/guest clathrate structure. The clathrate, with composition 2Sr@B 6 C 6 , exhibits the cubic bipartite sodalite structure (type VII clathrate) composed of sp 3-bonded truncated octahedral C 12 B 12 host cages that trap Sr 2+ guest cations. The clathrate not only maintains the robust nature of diamond-like sp 3 bonding but also offers potential for a broad range of compounds with tunable properties through substitution of guest atoms within the cages.

Journal of physics, May 7, 2014

Bulletin of the American Physical Society, Jun 16, 2015

Submitted for the SHOCK15 Meeting of The American Physical Society Cyanoacetohydrazide under pres... more Submitted for the SHOCK15 Meeting of The American Physical Society Cyanoacetohydrazide under pressure 1 GUSTAV BORSTAD, JEN-NIFER CIEZAK-JENKINS, US Army Research Laboratory-The application of pressure to molecular crystals generates dramatic changes in the properties through the modification of the intermolecular interactions, the crystal structure, and the molecular bonding. Typical changes as the density increases involve the breaking of chemical bonds and the formation of new bonds. This results in the increase in the coordination number and the formation of polymers. The novel materials thus produced may possess novel properties such as high-energy density, super-hardness, high electrical and thermal conductivities and optical activity. Nevertheless, recovering these novel materials to ambient conditions has proven challenging. One approach to overcome this is seeking appropriate chemical precursors which will yield enhanced stability of the recovered material. In this poster, we present Raman data of cyanoacetohydrazide compressed using diamond anvil cell techniques. These data suggest evidence of an irreversible transformation near 20 GPa. The characteristics and stability of the recovered sample are also discussed.

Thesis (Ph.D.), Department of Physics and Astronomy, Washington State UniversityWe have investiga... more Thesis (Ph.D.), Department of Physics and Astronomy, Washington State UniversityWe have investigated the DDepartment of Physics, Washington State Universit

Nucleation and Atmospheric Aerosols, 2018

LLM-172 or 3, 4-bis (4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole has been studied experimental... more LLM-172 or 3, 4-bis (4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole has been studied experimentally and computationally modeled at high-pressure. Minimum enthalpy structures were relaxed using norm-conserving pseudo potentials which provided a high level of convergence for the final computational structures. The calculated P-V curve fits reasonably well to the experimental X-ray diffraction data. No phase transitions or deviations from the P212121 (D2-4) space group of the LLM-172 crystal were observed to near 35 GPa, although slight modifications to the molecular geometry were noted in the Raman spectra. Density functional perturbation theory was used to obtain calculated Raman spectra; these calculated spectra were then used for comparison with experimental Raman spectra and the identification of the atomic motions associated with the vibrational modes. Based upon the modification of the experimental Raman spectra with pressure potential decomposition mechanisms are proposed. Quantum mechanical molecular dynamics (QM MD) calculations of LLM-172 surfaces resulted in determination of the very first fragments decomposed from the surface at high temperatures.

Applied Physics B, 2007

A three-laser heterodyne system was used to measure the frequencies of twelve previously observed... more A three-laser heterodyne system was used to measure the frequencies of twelve previously observed far-infrared laser emissions from the partially deuterated methanol isotopologues 13 CD 3 OH and CHD 2 OH. Two laser emissions, a 53.773 μm line from 13 CD 3 OH and a 74.939 μm line from CHD 2 OH, have also been discovered and frequency measured. The CO 2 pump laser offset frequency was measured with respect to its center frequency for twenty-four FIR laser emissions from CH 3 OH, 13 CD 3 OH and CHD 2 OH.

Bulletin of the American Physical Society, Jul 12, 2013

are studied due to their importance in revealing fundamental properties and giving rise to novel ... more are studied due to their importance in revealing fundamental properties and giving rise to novel behaviors as well as the hope of using the currently known and remarkable properties of hydrogen for applications. The hydrogen molecule (and its isotopic forms) is of interest in its own right as the simplest molecule, yet it forms an extremely complicated solid with many interesting properties observed or expected to be observed under high pressure. Furthermore, the novel behavior observed in simple binary mixtures of hydrogen and simple molecular systems, such as water, ammonia, and methane, where the mixture alters the structure and properties of both systems, giving rise to a new system different from either specie alone. This provides interesting insights into the effects of the environment on these molecules and on their resulting interactions and properties. In this talk, we will present a summary of the results obtained from Raman spectroscopic studies on these systems, and we will compare and contrast the properties of these hydrogen-rich mixtures as the simple molecular species is varied.

Bulletin of the American Physical Society, Mar 19, 2013

mixtures under pressure are of interest as fundamental systems in physics and chemistry as they a... more mixtures under pressure are of interest as fundamental systems in physics and chemistry as they allow the effects of the environment on the behavior of different chemical compounds to be examined. Furthermore, mixtures of simple molecular systems are of interest for applications in fuel cells and also to planetary science due to their presence in the interiors of the giant gas planets. In this presentation, Raman data on the ammonia and hydrogen system under pressure will be presented, and the extent and nature of the interactions in this mixture will be discussed.

Journal of Physical Chemistry A, Apr 22, 2016

Journal of Chemical Physics, Jan 28, 2014

We have investigated high-pressure behaviors of simple binary mixtures of NH3 and D2 to 50 GPa an... more We have investigated high-pressure behaviors of simple binary mixtures of NH3 and D2 to 50 GPa and CH4 and D2 to 30 GPa using confocal micro-Raman spectroscopy. The spectral data indicate strong proton exchange reactions occur in dense D2-NH3 mixture, producing different isotopes of ammonia such as NH3, NH2D, NHD2, and ND3. In contrast, the proton exchange process in dense D2-CH4 mixture is highly limited, and no vibration feature is apparent for deuterated methane. The vibrational modes of H2 isotopes in D2-NH3 are blue shifted from those of pure H2 isotopes, whereas the modes of D2-CH4 show overall agreement with those in pure D2 and CH4. In turn, this result advocates the presence of strong repulsion and thereby internal pressure in D2-NH3 mixture, which are absent in D2-CH4. In fact, the bond length of hydrogen molecules in D2-NH3, calculated from the present spectral data, is shorter than that observed in pure hydrogen – supporting the enhanced intermolecular interaction in the mixture. Comparing the present spectral results with those previously observed in D2-H2O mixtures further suggests that the strength of repulsive interaction or the magnitude of internal pressure in the mixtures is proportional to the strength of hydrogen bonding in H2O, NH3, and CH4 in decreasing order. Hence, we suggest that the proton exchange is assisted by hydrogen bonding in these molecules.

Angewandte Chemie, Dec 9, 2020

It has not been through the copyediting, typesetting, pagination and proofreading process, which ... more It has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.