Malcolm Nicol's Research Interest
My
research aims to develop better ways of thinking about materials under extreme
conditions: pressures to more than 1 million atmospheres, temperatures to more
than 8000 K, and times from 30 psec to the age of the planets. Current
activities focus around the UNLV High Pressure Science and Engineering Center
(HIPSEC).
Besides laboratories on campus, HIPSEC is a leader of the High Pressure
Collaborative Access Team (HPCAT) that built and runs a world-class facility
for X-ray diffraction and spectroscopy at the Advanced Photon Source of Argonne
National Laboratory.
In the past, my group innovated applying Mössbauer and Raman spectra at high
pressures and showed that iron is not ferromagnetic under conditions in the
Earth's core; froze oxygen at room temperature for the first time, measured its
melting curves to 700 K and the melting curve of N2 to 1000 K; discovered d-
and e-O2; showed the general
instability of multiply‑bonded carbon at very high pressures by studying polymers of CO, C2N2,
HCN, COCl2 and alkyl‑ and alkoxy‑ naphthalenes; determined
the structures of e-O2 and
polymeric CO2-V; and built at SSRL the x-ray diffractometer for the
UC-National Labs PRT
Recent advances include: synthesizing cubic-BN
and b-Si3N4
directly from the elements;discovering the ionic dimer of carbon dioxide, CO++CO3=,
and solving the structure of this and several other phases of solid CO2;
developing a new pressure measuring system based on Raman spectra of 12C
and 13C diamond; and defining the nature of the cubic-hexagonal
closest packed structural transformation of solid xenon. Much of our
experimental work is done in collaboration with Prof. Cornelius and Pravica,
their groups, other members of the HIPSEC team
and scientists at DOE national laboratories. All of them can help to advance a
project.
We are working to define better pressure media for high-pressure (million-atmosphere)
research, to develop new high-pressure cells, to do micro-absorption
spectroscopy on samples of high explosives and other reactive materials, and to
synthesize new materials that may be harder than diamond. During this summer,
we also want to develop a sapphire-anvil cell that contains samples of
millimeter dimensions; that is, at least 200 times the volumes of current
cells. Other devices involving SiC anvils might be tested. Both would be
valuable for high-pressure spectroscopy, synthesis, and neutron diffraction
work.
Another interesting problem for the summer might be to test potential synthetic routes
to produce macroscopic quantities of a new, possibly hard, carbon nitride. In
addition to work at UNLV, this should involve at least a few days taking X-ray data at HPCAT.
With Prof. Pravica’s group, we are studying the structures and properties of high explosives at high pressures. We recently discovered a new high-pressure phase of PETN and want to define the transition conditions and to characterize it by Raman spectroscopy, X-ray spectroscopy and
diffraction. A summer student could establish the phase boundary, analyze the
vibrational spectrum of the new phases, and help to solve its structure.
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