From to Universe Physical Research Stephen Lepp

• Professor of , Department of and Astronomy • Ph.D., Physics, University of Colorado, Boulder • BPB 234, [email protected] • http://www.physics.unlv.edu/~lepp/

Areas of Expertise • • Interstellar Medium • SN1987A • Formation of first objects in the Early Universe • Thermal Phases in Astrophysics • X-ray chemistry Research Summary: I primarily at the intersection of Atomic and with Astrophysics. Making models of astronomical environments to further our understanding of them. I have modeled: interstellar clouds, star forming regions, active galactic nuclei, SN1987A, and the Early Universe. Quantum Information and

1 0 ) -1 -1 cm

Quantum Control of 3 -2 -3 -4 KRb + K -5 Potential (10 K2 +Rb Chemical Reactions -6 6 10 6 10 14 14 18 18

Balakrishnan Naduvalath RKK (a0) RKRb (a0) Department of Chemistry & , pathway in UNLV ultracold K+KRb collisions. Quantum engineered KRb Areas of Expertise have been prepared • Ultracold Molecules at 300 nK. Ultracold polar • Ultracold Quantum Engineered Chemistry molecules such as KRb are potential candidates for • Quantum control of chemical reactions quantum computing and • Geometric effect in chemistry quantum information • Stereodynamic control of chemical processing. reactions $$$: NSF, DOD, NASA Controlling reaction outcome through quantum interference

O + HO eV loop 4.5 Left panel: Two paths for a chemical reaction. n H + O2 4 These two paths can interfere constructively or

2 destructively, maximizing or minimizing the

Looping pathway . This quantum effect becomes 0 magnified in the ultracold regime (Kendrick,

-1.76 Hazra, and Balakrishnan, Nature Comm. 6, 7918 O + HO (2015). ndirect H + O2

Direct pathway -13 O + OH(v=0, j=0) H + O 2 (v’=2, j’=1) with geometric phase -14

Right panel: The nature of the interference can 2 be controlled by including “geometric phase”. -15 In the image on the right, inclusion of the -16

geometric phase enhances the reactivity. The /Sr cm log(DCS) no geometric phase (that correctly describes the -17 180 sign of the wave function near a conical geometric 140 phase 100 -18 60 intersection with an excited electronic state) -6 -5 -4 -2 20 acts as a “quantum switch” (Hazra, log(Ec) K -1 0 scattering angle (deg) Balakrishnan, and Kendrick, J. Phys. A 119, 12291 (2015) References

• P. G . Jambrina, J. F. E. Croft, H. Guo, M. Brouard, N. Balakrishnan, and F. J. Aoiz, Stereodynamical control of a quantum scattering resonance in cold molecular collisions, Phys. Rev. Lett. 123, 043401 (2019). • J. F. E. Croft and N. Balakrishnan, Controlling rotational quenching rates in cold molecular collisions, J. Chem. Phys. 150, 164302 (2019). • K. Hilsabeck, J. Meiser, M. Sneha, N. Balakrishnan, and R. N. Zare, Photon of Deuterium iodide photodissociation, Phys. Chem. Chem. Phys. 21, 14195 (2019). • J. F. E. Croft, N. Balakrishnan, M. Huang, and H. Guo, Unreveling the stereodynamics of cold controlled HD-H2 collisions, Phys. Rev. Lett. 121, 113401 (2018). (Editor’s choice). • J. F. E. Croft, C. Makrides, M. Li, A. Petrov, B. K. Kendrick, N. Balakrishnan, and S. Kotochigova, Universality and chaoticity in ultracold K+KRb chemical reactions, Nature Comm. 8, 15897 (2017). • N. Balakrishnan, Perspective: Ultracold molecules and the dawn of cold controlled chemistry, J. Chem. Phys. 145, 150901 (2016). • B. K. Kendrick, J. Hazra, and N. Balakrishnan, The Geometric Phase Appears in the Ultracold Hydrogen Exchange Reaction, Phys. Rev. Lett. 115, 153201 (2015). • B. K. Kendrick, J. Hazra, and N. Balakrishnan, The Geometric Phase Controls Ultracold Chemistry, Nature Communications 6, 7918 (2015). Technetium and Uranium Chemistry Frederic Poineau, Ph.D. àSynthetic and coordination chemistry Technetium binary and ternary halide compounds Compounds with multiple metal-metal bonds

Tc 2Cl4(PMe3)4 TcCl 2 : a unique structure-type àChemistry relevant to remediation and fuel cycle applications Separation, vitrification, and waste forms (alloys)

Preparation of U-Tc alloys by arc melting Demonstration of the separation of uranium from technetium for fuel cycle application Technetium and Uranium Chemistry Frederic Poineau, Ph.D. Radiochemistry àCollaborative work relevant to nuclear forensics Analysis of Uranium Isotopic Ratios by Thermal Ionization (TIMS)

• Uranium compounds found throughout the fuel cycle (UO2, U3O8, UF4) prepared at UNLV • 235U/238U isotopic ratio measurements using TIMS at LANL

Uranium samples prepared at UNLV 235U/238U Isotopic ratio: 80%