Sokol Research Group: Indiana University Bloomington

Sample cell used in millikelvin neutron scattering studies attached to the cold stage of a dilution refrigerator

Behavior of micelles studied with SANS (*Das et. al. Langmuir 28, 11962*)

Research

Our work focuses on the study of the structure and dyanmics of condensed matter systems under confinement at the nanoscale. Confinement in nanometer size pores or on surfaces can drastically affect the properties of confined systems ranging from classical solids to quantum liquids and can even lead to new phases not present in the bulk. We use neutron and x-ray scattering to probe the microscopic structure and dynamics of these confined systems.

Featured Articles

**Bulklike excitations in nanoconfined liquid helium, Bryan, M. S., Prisk, T. R. Sherline, T. E., Diallo, S. O., & Sokol, P. E. Physical Review B, 95(14), 144509.** High resolution inelastic neutron scattering studies of the the roton in nanoscale confined helium show that the lifetime is the same as in the bulk liquid. At low temperatures this corresponds to a mean free path thousands of times longer than the pore size implying that the lifetime is not set by the scale of the confinement.

**Diffusive and rotational dynamics of condensed n-H₂ confined in MCM-41. Prisk, T. R., Bryan, M. S., & Sokol, P. E. (2014). *Physical Chemistry Chemical Physics : PCCP*, 16(33), 17960–74.** Inelastic neutron scattering is used to study the diffusive and rotational dynamics of hydrogen molecules confined in 3.5 nm pores of MCM-41. The studies provide information of the orientational potential at the surface which leads to selective adsorption of ortho-H2.

The new cold neutron chopper spectrometer at the Spallation Neutron Source: Design and performance. Ehlers, G., Podlesnyak, a. a., Niedziela, J. L., Iverson, E. B., & Sokol, P. E. (2011). *Review of Scientific Instruments*, 82(8), 85108. The Cold Neutron Chopper Spectrometer (CNCS) is a world class inelastic spectrometer at the Spallation Neutron Source. The design and construction of the instrument was a join effort between the Sokol Group and Oak Ridge National Lab.

Group News

June 21, 2018 - Moving into the new lab

Moving equipment into the new lab in the renovated Swain Hall. Looks like most of the utilities are ready - unlike our temporary relocation to MESH Hall.

June 19, 2018 - Moving Day

Two rotating anode x-ray generators are loaded onto a flat bed trailer for the move back to Swain Lab. Fortunately the rain predicted for the day held off until the move was complete.

June 15, 2018 - Getting ready for move to renovated Lab

After 2 years in temporary lab space at the Multidisciplinary Engineering and Science Hall the lab is getting prepared to move back to newly renovated laboratory space in Swain Hall.