Daniel Sneed

Daniel Sneed_with spectrometer

UNLV Physics and Astronomy
High Pressure Science and Engineering Center
Masters Student, 1st Year
Graduate Assistant
B.S. Physics
University of Nevada, Las Vegas, 2014
A.A.S Network Engineering
Great Basin College, 2010

 

 

Materials Under Extreme Conditions: Hard X-ray Induced Chemistry

Working with gases under high pressures can be extremely difficult do to the difficulty in loading techniques. Using only hard x-rays, our group has been able to produce gases within a diamond anvil cell. By taking advantage of the highly penetrating and ionizing qualities of hard x-rays, we have been able to decompose certain inert compounds and produce gases (N2, H2, O2, Cl2, and F2). We have also been able to create water by reacting H2 and O2 in a diamond anvil cell.

Currently I am working on a project involving reacting fluorine gas with cesium fluoride under pressures greater than 20 GPa in order to form higher oxidation states of cesium.  This work is inspired by a paper published in Nature called “Caesium in high oxidation states and as a p-block element” postulating that under given pressures cesium will undergo p-shell bonding with up to 6 flouring ions. The implication of this research is that it could prove that bonding doesn’t have to occur using only valence electrons, but can also occur using inner shell electrons given the proper conditions.

 

Publications:

1.    “Measurement of the Energy Dependence of X-ray Induced Decomposition of Potassium Chlorate,”  M. Pravica, D. Sneed, L. Bai, C. Park, Journal of Applied Crystallography (2013)

2.    “Studies of carbon tetrachloride at extreme conditions,” M. Pravica, D. Sneed, Y. Wang, Q. Smith, and G. Subrahmanyam, Journal of Chemical Physics, 140, 194503 (2014)

3.    “X-ray induced mobility of molecular oxygen at extreme conditions,” Michael Pravica, Dmitry Popov, Stanislav Sinogeikin, Daniel Sneed, Griffin Guardala, and Quinlan Smith, Applied Physics Letters (2013)

4.    “Effect of Pressure and Temperature on Structural Stability of MoS2”, Nirup Bandaru, Ravhi S. Kumar, Daniel Sneed, Oliver Tschauner, Jason Baker, Daniel Antonio, Sheng-Nian Luo , Thomas Hartmann , Yusheng Zhao, and Rama Venkat, J. Phys. Chem. C, 2014, 118 (6), pp 3230–3235 (2014)

5.    “High pressure X-ray photochemical studies of carbon tetrachloride: Cl2 production and segregation,” Michael Pravica, Daniel Sneed, Quinlan Smith, and Ligang Bai, Chemical Physics Letters, Volume 590, 18 December 2013, Pages 74-76

6.    “Note: Loading method of molecular fluorine using x-ray induced chemistry,” M. Pravica, D. Sneed, M. White, and Y. Wang, Review of Scientific Instruments, 85, 086110 (2014)

7.    “Communication: A novel method for generating molecular mixtures at extreme conditions: The case of hydrogen and oxygen,” M. Pravica, D. Sneed, M. White, and Y. Wang, The Journal of Chemical Physics, 141, 091101 (2014)

Presentations:

1.     “Studies in useful hard x-ray induced chemistry” APS-AIRAPT joint conference, Seattle, WA, July 11 2013

2.    “High Pressure Raman and X-ray diffraction studies on MoS2 up to 51 GPa” Poster presentation at the APS-AIRAPT joint conference, Seattle, WA, July 8, 2013

3.    “Studies in Useful hard x-ray induced chemistry: Urea and CCl4 under extreme conditions” Poster presentation at the APS-AIRAPT joint conference, Seattle, WA, July 7, 2013

4.     “Studies in Useful hard x-ray induced chemistry: Urea and CCl4 under extreme conditions” Poster presentation at the 2013 Stewardship Science Academic Programs (SSAP) Annual review symposium, Albuquerque, NM, June 27, 2013

5.    “Studies of x-ray induced decomposition of alkali halates” Poster presentation at the 2013 Stewardship Science Academic Programs (SSAP) Annual review symposium, Albuquerque, NM, June 27, 2013

6.    “Studies of Molecular Diffusion Under Extreme Conditions”, Poster presentation at the 2014 Stewardship Science Academic Programs (SSAP) Annual review symposium, Bethesda, MD, February 19, 2014

 

Awards:

1.    First undergraduate to ever receive best poster award at the 2014 Stewardship Science Academic Programs (SSAP) Annual review symposium, Bethesda, MD, February 19, 2014

 

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