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
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).
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).
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.