William W. Shum

Theoretical, Physical, and Materials Chemistry

Condensed Matter Physics

B.S., Ph.D., University of Utah

(Currently at Cornell University)

Research Interests:

Magnetic Interactions in Novel Molecule-based Materials

The development of molecule-based materials with unusual magnetic properties leads to new science and technology. My research utilized both theoretical and physical approach to deeply understand the electronic and magnetic properties of molecule-based materials. Novel molecule-based materials are synthesized by molecular and organic building blocks such as tetracyanoethylene leads to potentially new applications such as molecular-switches and spintronics.
The understanding of their electronic structures and magnetic interactions is essential. In my research, I utilize both theoretical and experimental methods to study properties of molecule-based materials, from molecular building blocks to metal-radical molecule-based magnets to three dimensional extended structures. Computational simulations (such as Hartree-Fock-based methods and density functional theory) are used to study their electron and spin correlation which leads to magnetic ordering. The spin interactions of such materials have been extensively studied by both computational simulations and physical experiments.

Computational simulated ferrimagnetic spin density of the 2-D layered [Fe(TCNE)(NCMe)2][FeCl4] organic-based magnet (Phys. Rev. B2009, 80, 64403.)	Hc(T) magnetic phase diagram of [Ru2(O2CMe)4]3[Cr(CN)6] (J. Phys. Chem. C2008, 112, 7936-7938.)
Interpenetrated Lattice [Ru2(O2CMe)4]3[Cr(CN)6]	Magnetic hysteresis of [Ru2(O2CMe)4]3[Cr(CN)6] as a function of pressure. (Adv. Mater.2007, 19, 2910-2913.)

Bonding of tetracyanobenzene [TCNB].- radical anion leads to fractionally charge sharing triad [TCNB]32-. (Angew Chem. Int. Ed. 2006, 45, 5322.)

SOMO for [TCNB].-	au HOMO of [TCNB]32-

Calculated singly occupied molecular orbital (SOMO) for [TCNB].- and the 2-electron-12-center (2e-/12c) bonding orbital for the fractional charge sharing [TCNB]32-.

Education:

B.S. University of Utah

Ph.D. University of Utah

Awards:

Cheves T. Walling Graduate Research Prize

University of Utah Department of Chemistry Graduate Poster Session Award

University of Utah Graduate Research Fellowship

Publications: (24 Articles)

"Giant Antiferromagnetically Coupled Moments in a Molecule-Based Magnet with Interpenetrating Lattices"
Fishman, R. S.; Okamoto, S.; Shum, W. W.; Miller, J. S. Phys. Rev. B2009, 80, 064401. [5 pages]

"Spin Polarized Electronic Structure for the Layered Two-Dimensional [FeII(TCNE)(NCMe)2][FeIIICl4] Organic-based Magnet"
Shum, William. W.; Epstein, Arthur. J.; Miller, Joel. S. Phys. Rev. B2009, 80, 064403. [6 pages]

"The Tetracyanopyrazinide Dimer Dianion, [TCNP]22-. 2 Electron 8 Center (2e-/8c) Bonding"
Novoa, Juan J.; Stephens, Peter W.; Weerasekare, Mahika; Shum, William W.; Miller, Joel S. J. Am. Chem. Soc.2009, 131, 9070-9075.

"Direct Evidence of electron Spin Polarization of the Organic-based Magnet [FeII(TCNE)(NCMe)2][FeIIICl4]"
Caruso, A. N.; Pokhodnya, K. I.; Shum, W. W.; Ching, W. Y.; Anderson, B.; Bremer, M. T.; Vescovo, E.; Rulis, P.; Epstein, A. J.; Miller, J. S. Phys. Rev. B2009, 79, 195202. [5 pages]

"Tristabilty Arising From Singlet-Triplet and Quartet Spin States for Dimeric CoII(Salen)"
Min, Kil Sik; Arthur, Jordan; Shum, William W.; Bharathy, Muktha; Zur Loye, Hans-Conrad; Miller, Joel S. Inorg. Chem.2009, 48, 4593-4594.

"Structure and Magnetic Interactions in the Organic-based Ferromagnet Decamethylferrocenium Tetracyanoethenide, [FeCp*2].+[TCNE].-"
Her, Jae-Hyuk; Stephens, Peter W.; Ribas-Arino, Jordi; Novoa, Juan J.; Shum, William W.; Miller, Joel S. Inorg. Chem.2009, 48, 3296-3307.

"Preparation and Structure of [CrIII2F3(TPyA)2](BF4)3[TPyA = Tris(2-pyridylmethyl)amine] Possessing Terminal and Bridging Fluorides"
Zhu, Q.; Nelson, K. J.; Shum, W. W.; DiPasquale, A.; Rheingold, A. L.; Miller, J. S. Inorg. Chim. Acta2008, 362, 595-598.

"Irreversible Magnetic Bistability and Nucleation of Magnetic Bubbles in Layered 2D Organic-based Magnet [Fe(TCNE)(NCMe)2][FeCl4]"
Yoo, J.-W.; Prigodin, V. N.; Shum, W. W.; Pokohdnya, K. I.; Miller, J. S.; Epstein, A. J. Phys. Rev. Lett.2008, 101, 197206. [4 pages]

"Structure and magnetic properties of LnIII[Ru2(CO3)4].8H2O"
Her, Jae-Hyuk; Kennon, Bretni S.; Shum, William W.; Stephens, Peter W.; Miller, Joel S. Inorg. Chim. Acta2008, 361, 3462-3464.

"Magnetic Ground State and Phase Diagram, Hc(T), for Magnetically Ordered [Ru2(O2CMe)4]3[Cr(CN)6]"
Shum, William W.; Schaller, Jason N.; Miller, Joel S. J. Phys. Chem. C2008, 112, 7936-7938.

"Observation of the pressure dependent reversible enhancement of Tc and loss of the anomalous constricted hysteresis for [Ru2(O2CMe)4]3[Cr(CN)6]"
Shum, William W.; Her, Jae-Hyuk; Stephens, Peter W.; Lee, Yongjae; Miller, Joel S. Adv. Mater.2007, 19, 2910-2913.

"Structure and Magnetic Ordering of KxH1-xNi(OH2)4[Ru2(CO3)4].zH2O"
Kennon, Bretni S.; Her, Jae-Hyuk; Stephens, Peter W.; Shum, William W.; Miller, Joel S. Inorg. Chem.2007, 46, 9033-9035.

"Control of Two-Electron Four-Center (2e-/4c) C-C Bond Formation Observed for Tetracyanoethenide Dimerization, [TCNE]22-"
Novoa, Juan J.; Ribas-Arino, Jordi; Shum, William W.; Miller, Joel S. Inorg. Chem.2007, 46, 103-107.

"The structure of fractionally charged tetracyanobenzenen- present in [TCNB]32-"
Bagnato, Joshua D.; Shum, William W.; Strohmeier, Mark; Grant, David M.; Arif, Atta M.; Miller, Joel S. Angew. Chem. Int. Ed.2006, 45, 5322-5326.

"Structure and Magnetic Properties of a Hydroxo-Bridged Copper(II) Distorted Cubane Stabilized via Supramolecular Hydrogen Bonding with an Ionic Hexafluoroacetylacetonate"
Lopez, Nazario; Vos, Thomas E.; Arif, Atta M.; Shum, William W.; Noveron, Juan C.; Miller, Joel S. Inorg. Chem.2006, 45, 4325-4327.

"Interpenetrating-lattice-structured magnets exhibiting anomalous magnetic properties"
Miller, Joel S.; Vos, Thomas E.; Shum, William W. Adv. Mater.2005, 17, 2251-2254.

"Structure and Magnetic Properties of (meso-Tetraphenylporphinato)manganese(III) Bis(dithiolato)nickelates"
Dawe, Louise N.; Miglioi, Jesse; Turnbow, Laura; Taliaferro, Michelle L.; Shum, William W.; Bagnato, Joshua D.; Zakharov, Lev N.; Rheingold, Arnold L.; Arif, Atta M.; Fourmigue, Marc; Miller, Joel S. Inorg. Chem.2005, 44, 7530-7539.

"The myth of cyanide always being a strong-field ligand: Synthesis and structural characterization of homoleptic S = 2 pentacyanochromate(II), [CrII(CN)5]3-, and nonacyanodichromate(II), [CrII(CN)9]5-"
Nelson, Kendric J.; Giles, Ian D.; Shum, William W.; Arif, Atta M.; Miller, Joel S. Angew. Chem. Int. Ed.2005, 44, 3129-3132.

"Diruthenium Tetraacetate Monocation, [RuII/III2(O2CMe)4]+, Building Blocks for 3-D Molecule-Based Magnets"
Vos, Thomas E.; Liao, Yi; Shum, William W.; Her, Jae-Hyuk; Stephens, Peter W.; Reiff, William M.; Miller, Joel S. J. Am. Chem. Soc.2004, 126, 11630-11639.

"Zero-Field Splitting, Field-Dependent Magnetization of Mixed-Valent S = 3/2 Diruthenium(II,III) Tetracarboxylates"
Shum, William W.; Liao, Yi; Miller, Joel S. J. Phys. Chem. A2004, 108, 7460-7462.

"One- and Two-Step Spin-Crossover Behavior of [FeII(isoxazole)6]2+ and the Structure and Magnetic Properties of Triangular [FeIII3O(OAc)6(isoxazole)3][ClO4]"
Hibbs, Wendy; Van Koningsbruggen, Petra J.; Arif, Atta M.; Shum, William W.; Miller, Joel S. Inorg. Chem.2003, 42, 5645-5653.

"Novel coordination of dicyanamide, [N(CN)2]-: preferential binding of the amide nitrogen"
Marshall, Shireen R.; Incarvito, Christopher D.; Shum, William W.; Rheingold, Arnold L.; Miller, Joel S. Chem. Comm.2002, 24, 3006-3007.

"Synthesis and Magnetic Properties of 3-D [RuII/III2(O2CMe)4]3[MIII(CN)6] (M = Cr, Fe, Co)"
Liao, Yi; Shum, William W.; Miller, Joel S. J. Am. Chem. Soc.2002, 124, 9336-9337.

"Corner Sharing Tetrahedral Network in Co3(HAT)[N(CN)2]6(OH2)2 (HAT = 1,4,5,8,9,12-Hexaazatriphenylene)"
Marshall, Shireen R.; Rheingold, Arnold L.; Dawe, Louise N.; Shum, William W.; Kitamura, Chitoshi; Miller, Joel S. Inorg. Chem.2002, 41, 3599-3601.

Funding and Support Provided by:

The University of Utah	Center for High Performance Computing

U.S. Department of Energy	American Chemical Society	Air Force Office of Scientific Research

Last Updated: August 2009