Atoms and molecules adsorbed (deposited) on carbon nanotube bundles (CNTB) are

1. Atoms and molecules adsorbed (deposited) on carbon nanotube bundles (CNTB) are interesting for scientific and practical reasons. On the scientific side novel one- and two- dimensional (1d, 2d) forms of matter may be fabricated on CNTB. On the practical side the storage capacity of CNTB, especially for hydrogen and organic molecules, has attracted attention. We are studying the 1d and 2d thermal and structural properties of atoms and molecules, including deuterium, deposited on CNTB. We use heat capacity, vapor pressure and neutron scattering measurements. Matter in 1d should have no phase transitions above T=0K, a prediction we have been able to verify in the 1K to 20K range. See neutron scattering results in Phys. Rev. B, 71, 155411 (2005), Phys. Rev. B, 70, 035410 (2004). Heat of adsorption (+) and heat capacity isotherms [2K (bottom), 3K and 4K (top)] vs. the amount adsorbed, first layer on CNTB. A: hydrogen, B: helium. Adsorption goes on: 1) Imperfect sites (1d), 2) Outer grooves, see inflection at 9 ccSTP (1d, 2d), and 3) The outside surface of bundle up to layer completion (2d) (for H2, dip in heat capacity isotherm at 22.5 ccSTP). T. A. Wilson’s PhD dissertation, U. of Washington (2004), J. Low Temp. Phys. 134, 115 (2004). Novel One- and Two-dimensional SystemsO. E. Vilches and L. B. Sorensen, U. of WashingtonDMR-0245423

2. Education: Recently, eleven undergraduate (U) and one REU student have participated in this program, with eight having graduated and gone to either graduate school or work in the private sector, as follows: Vandervelde (Illinois), Schneble (Cambridge), Higgins (Irvine), Ramunno- Johnson (UCLA), Winters (Colorado State), Batchellor (UW), Horn, Davis, Holmes (REU). Tate Wilson (Ph.D. ’04) is a post-doc at U. Mass., Amherst. Current students: Natasha Nichols (MSc), Subramanian Ramachandran (PhD), Dario Machleidt (U), Jeremy Morales (U) and Kevin Dillon (U). Societal Impact: Work on these projects has proven very appealing to undergraduates: a blend of nanophysics (carbon nanotubes), low temperatures (working with liquid helium), learning about and supporting thermodynamic and neutron scattering measurements by doing their own experiments, and working with and programming LabView controlled experiments gives them a nice set of working tools for graduate studies or employment in the private sector. We have attracted excellent graduate students and could have a larger group if funds would allow it. Novel One- and Two-dimensional SystemsO. E. Vilches and L. B. Sorensen, U. of Washington,DMR-0245423