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SSRL Headlines Vol. 7, No. 1 July, 2006
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Contents of this Issue:
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1. Science Highlight —
An Octahedral Iron(VI) Complex - A Novel Form of Iron
(contact:
S. DeBeer George, serena@slac.stanford.edu)
Chemists have synthesized and characterized a new, highly reactive form of iron
that promises to deepen our understanding of this important element. Iron is
found in abundance in the natural world, and in its ionized form plays a
crucial role in virtually all living processes.
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Proposed Fe(VI)-nitrido photolysis product.
|
An iron
atom can have as many as eight valence electrons in its outer shell,
but most typically iron has five or six of these valence electrons. The new
form of iron, designated iron(VI), has only two electrons in its outer shell,
making it very electron deficient and thus highly reactive. Only one other form
of iron(VI), ferrate, which is tetrahedrally coordinated by four oxygen atoms,
is known. Ferrate is a powerful oxidant, but reacts indiscriminately and thus
can be difficult to use. The new species of iron(VI) which is octahedrally
coordinated, instead forms a bond with nitrogen, which results in different
reactivity, and thus holds promise for industrial and biomedical applications.
"We hope that this complex will have practical advantages over other iron
compounds, and we might expect that it does based on its structure," explained
John F. Berry, an Alexander von Humboldt postdoctoral fellow at Germany's
Max-Planck Institute for Bioinorganic Chemistry in Mulheim. Berry is lead
author of the paper describing the new compound, which was originally published
in Science Magazine's online publication, Science Express.
http://www.sciencemag.org/cgi/content/abstract/1128506v1
The research team, which included scientists from the Max-Planck Institute for
Bioinorganic Chemistry in Germany and the Stanford Synchrotron Radiation
Laboratory, conducted x-ray absorption spectroscopy (XAS) experiments at SSRL's
Beam Line 9-3 to characterize the new complex. The XAS studies, combined with
other spectroscopic results and theoretical calculations, were key in
establishing the electronic and geometric structure of this novel compound.
To learn more about this research see the full technical highlight at:
http://www-
ssrl.slac.stanford.edu/research/highlights_archive/FeVI.html
2. Science Highlight —
Ordered Nanoporous Germanium Semiconductors
(contact:
S. Tolbert, tolbert@chem.ucla.edu)
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Schematic of the Zintl cluster/ surfactant co-assembly process.
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Porous nanoscale materials often have useful properties because of their
proportionally large surface areas. Now, UCLA scientists have devised a way to
make porous germanium, a semiconductor used in fiber optics and electrical
components. This discovery means that nanoporous materials could soon be used
to develop new kinds of solar cells or highly sensitive electronic sensors.
Until now chemists have had difficulty forming germanium that contains
regularly spaced, nanoscale holes. Previous nanoporous materials were made from
oxides, which are ideal for use as catalysts but have only a narrow range of
usefulness in electronics. Using a technique called "surfactant templating,"
UCLA chemist Sarah Tolbert and colleagues combined a soap-like molecule, or
"surfactant" with a special preparation of germanium molecules. Under the right
conditions these two components mix and arrange themselves into a honeycomb
lattice. The new compound is chemically treated to remove the surfactant,
leaving a skeleton of germanium with very thin walls.
Porous germanium prepared in this way has an enormous surface area - 500 square
meters per gram. That makes it ideal for use in highly sensitive sensors and
detectors, in which tiny traces of a material must adhere to a surface to be
detected.
Tolbert and her team used several approaches, one of which being extended x-ray
absorption fine structure (EXAFS) techniques at SSRL's Beam Lines 4-1 and 6-2,
to characterize these new nanoscale structures.
To learn more about this research see the full technical highlight at:
http://www-
ssrl.slac.stanford.edu/research/highlights_archive/ge.html
3.
SSRL Advisory Committees Convene in July
(contact:
J. Stöhr, stohr@slac.stanford.edu)
The SSRL Scientific Advisory Committee (SAC) convened on July 18-19 to provide
advice on SSRL programs. The meeting began with overview talks on SLAC and SSRL
on the first day, and a visit to the SSRL experimental floor. On the second
day, new facilities planned at SSRL were presented to the SAC for their advice
on whether the proposed facilities are state-of-the-art, complement and/or
strengthen existing SSRL programs, and allow SSRL to remain a forefront
synchrotron radiation facility. SSRL has always placed emphasis on innovation,
user support and excellence in selected areas. The selection of and investment
in "areas of excellence" is therefore especially important. The SAC is chaired
by Geri Richmond (University of Oregon).
http://www-ssrl.slac.stanford.edu/ssrl_sac.html
The SAC meeting followed the SSRL Proposal Review Panel meeting and the SSRL
Structural Molecular Biology Advisory Committee meeting, both on Monday, July
17. In their executive session, the PRP determined ratings based on the peer
reviews received for new proposals and proposal extensions submitted during
this last call for proposals.
http://www-ssrl.slac.stanford.edu/prp.html
4.
Share Your Research Results at SSRL33, October 12-13, 2006
(contact:
C. Knotts, knotts@slac.stanford.edu)
The 33rd Annual SSRL Users' Meeting, October 12-13, provides a forum for the
presentation and discussion of research activities from SSRL and the
synchrotron community. New data, developments and plans for the future will be
shared through talks, poster presentations, and workshops. There will be
presentations on new opportunities for imaging and ultrafast science,
structural biology, science highlights from the last year, and a young
investigators session. Submit an abstract to share your research results for an
oral presentation (by July 31) or a poster presentation (by September 20).
http://www-conf.slac.stanford.edu/ssrl/2006/
Please consider nominating your colleagues for one or more of the following
awards which will be presented at the SSRL33:
Your help is also needed to identify users who may be interested in serving on
the SSRLUOEC -- and you can nominate yourself! We are currently soliciting
nominations for five positions on the SSRLUOEC in the following disciplines:
materials/chemistry (2); biospectroscopy (1), macromolecular crystallography
(1), and a graduate student in any discipline. For more information, see
http://www-conf.slac.stanford.edu/ssrl/2006/nominations.htm
We look forward to an informative meeting, and encourage you to join us!
http://www-conf.slac.stanford.edu/ssrl/2006/default.htm
5.
The XAFS13 Conference a Success at Stanford and SSRL
(contacts: B. Hedman,
hedman@ssrl.slac.stanford.edu; P. Pianetta, pianetta@ssrl.slac.stanford.edu)
|  |
| E. Stern (middle) shown with joint recipients of the Edward Stern
Outstanding Achievement Award C. Natoli (left) and J. Rehr
(right). |
The 13th International Conference on X-ray Absorption Fine Structure (XAFS13)
was held at the Frances C. Arrillaga Alumni Center on Stanford University
campus, July 9-14. About 385 participants from all over the world enjoyed five
intense days of 7 plenary lectures, three parallel sessions of invited and
contributed talks each day, and three extensive poster sessions based on about
130 submitted poster abstracts for each day. A special session was held on the
first day as a Festschrift to the late Prof. Dale Sayers, to honor his many
great scientific contributions to the XAFS field. A tour of SSRL, whose staff
organized this international conference, attracted some 180 visitors, who
enjoyed posters and guided presentations of beam lines and science by SSRL
scientific staff. Three scientific awards were presented by the International
XAFS Society: the Dale Sayers Young Scientist Award for Applications of XAFS to
Jan-Dierk Grunwaldt, ETH Zurich; the Farrel Lytle Young Scientist Award for
Theory or Instrumentation to Pieter Glatzel, ESRF; and the Edward Stern
Outstanding Achievement Award jointly to Calogero (Rino) Natoli, INFN and John
Rehr, University of Washington. The Stanford Cantor Arts Center provided a
much appreciated venue for the conference dinner, and the participants enjoyed
the pleasant California environment during many ad-hoc meetings and
interactions throughout the conference. A Conference Proceedings book will be
published based on the ca. 260 contributions submitted and peer-reviewed during
the meeting.
6.
Beam Line Update
(contact: T. Rabedeau,
rabedeau@slac.stanford.edu)
Since the SPEAR3 upgrade in 2003-04, SSRL has implemented an aggressive
schedule of beam line upgrade/development projects to make all beam lines
compatible with 500-mA operations, which is the SPEAR3 design current. By the
end of 2006, the optics, beam transport components, and shielding of 14
insertion device branch lines and 6 bend magnet branch lines will have been
upgraded for 500-mA SPEAR3 power, while the remaining 3 insertion device branch
lines are scheduled for completion by the end of 2007. Additionally, a new beam
containment monitoring system required for 500-mA beam line operations will be
phased in during the FY2007 run. During the upcoming summer shutdown, a new,
sagittal focusing monochromator will be installed on BL7-2 and commissioned
later this year; user operations with vertically and horizontally focused beam
on BL7-2 are expected to resume later in the FY2007 user run. BL2 and BL8 will
get new beam position monitors (BPMs). BL4 is scheduled for a complete upgrade
for 500-mA SPEAR3 operations (and a move to the new SSRL Building 130) during
the second half of calendar year 2007. In the interim, although BL4-1 and BL4-3
remain closed, BL4-2 will continue to be available for structural molecular
biology small angle x-ray scattering and diffraction in 2006/2007 (currently
limited to 100 mA operations). A new in-vacuum undulator beam line for
macromolecular crystallography, BL12-2, is currently under construction with
commissioning to follow.
7.
National Academies Report Encourages AMO Research
A new report from the National Academies' National Research Council encourages
the U.S. to reinforce its commitment to research in atomic, molecular and
optical (AMO) science - the study of atoms, molecules, and light, and related
technologies such as lasers and fiber-optic communications (for the full
report, see
http://www.nap.edu/catalog/11705.html). The report, which
highlights six main "challenges" in physics that could directly impact the
technology and economy of the future, also stresses the importance of research
and education in the physical sciences. "What motivated this study were the
tremendous advances achieved in AMO science over the past several years," said
Philip Bucksbaum, committee co-chair, professor of SSRL and Applied Physics at
Stanford University, and the PULSE Director. "We can now use lasers to heat
matter to a million degrees or cool it to temperatures a billion times colder
than outer space. We can also use lasers as strobe lamps to take snapshots of
chemical reactions that last less than a millionth of a billionth of a second.
These investigations are not just revealing new fundamental science, but also
inspiring new innovations to overcome our greatest global challenges."
Stanford University has long played a leading role in technological advances in
computing and laser research, and will continue that tradition with the
completion of the world's first free-electron x-ray laser, the Linac Coherent
Light Source (LCLS), at SLAC in 2009. See the NAS press release at:
http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11705
8.
Artie Bienenstock Goes To Washington
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| A. Bienenstock receiving DOE award from P. Dehmer |
|
Arthur Bienenstock will be traveling to Washington in the near future to take
on the newly created position of Special Assistant to Stanford University's
president for federal research policy. Bienenstock, a professor at the Stanford
Synchrotron Radiation Laboratory and of Materials Science and Engineering and
of Applied Physics at Stanford University, was appointed Vice Provost and Dean
of Research and Graduate Policy in 2003. Bienenstock was elected Vice President
of the American Physical Society (APS) for 2006, and in accordance with the
organization's succession system, he will become President Elect in 2007,
President in 2008 and immediate Past President in 2009. As a senior science
adviser to President Clinton in the role of Associate Director for Science of
the White House Office of Science and Technology Policy from 1997 to 2001,
Bienenstock was a strong advocate for federal research funding and provided
guidance on complex scientific and policy issues. In his new leadership roles,
he plans to focus on issues including federal funding for research in the
physical sciences and engineering (with some emphasis on energy research) and
the maintenance of openness in research during a security-conscious era. At the
October 2005 SSRL Users' Meeting, Pat Dehmer, Associate Director of the Office
of Basic Energy Sciences, DOE, presented Bienenstock with a DOE Distinguished
Associate Award.
Ann Arvin, the Lucile Salter Packard Professor in Pediatrics, a professor of
microbiology and immunology, chief of the infectious diseases division of the
Pediatrics Department, and associate dean of research, will succeed Bienenstock
as Stanford's vice provost and dean of research, effective November 1.
9.
Excerpts from SLAC Today
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| X-ray scan of a
spider fang showing concentrations of zinc (in red). |
X-ray Microprobe at SSRL BL6-2.
The BL6-2 x-ray microprobe is a research
destination for scientists from all over the world interested in taking a
deeper look at the chemical make up of things, and in particular, what role
certain metals play. Three of these recent studies have sought a deeper
understanding of how such metals behave in some unusual organisms. Read more
...
http://today.slac.stanford.edu/feature/witches-brew.asp
Standing on the Shoulders of Robots. Over the past three years, the
macromolecular crystallography beam lines at SSRL have enjoyed a spike in
scientific demand, with more and more users from around the world taking
advantage of the technologies available for determining the structure of
molecules. Increasingly, those users are doing that work without setting foot
into the laboratory. Read more...
http://today.slac.stanford.edu/feature/remote_access.asp
10.
User Administration Update
(contact:
C. Knotts, knotts@slac.stanford.edu)
SSRL's current experimental run ends on Monday, August 7; user operations will
resume on most beam lines in early November 2006. The FY2007 SPEAR3 preliminary
operating schedule which includes information on scheduled maintenance and
accelerator physics studies, is available at:
http://www-ssrl.slac.stanford.edu/schedules/07_run_preliminary.pdf
Spokespersons with active X-ray/VUV proposals who are interested in requesting
beam time for the next scheduling period (November 2006-January 2007) must
submit beam time request by the August 14 deadline.
http://www-ssrl.slac.stanford.edu/users/user_admin/xray_btrf.html
http://www-ssrl.slac.stanford.edu/users/user_admin/vuv_btrf.html
A message will be sent to Macromolecular Crystallography spokespersons in
August regarding Beam Time Requests for the first scheduling period in the
FY2007 experimental run.
11.
Photon Science Job Opportunities
A number of positions are currently available at the LCLS, LUSI and SSRL.
Please refer to the Photon Science Job Openings page for more information about
these job opportunities.
http://www-ssrl.slac.stanford.edu/photonscience/
jobs.html
__________________________________________________________________________
SSRL Headlines is published electronically monthly to inform SSRL users,
sponsors and other interested people about happenings at SSRL. SSRL is a
national synchrotron user facility operated by Stanford University for the
U.S. Department of Energy Office of Basic Energy
Sciences. Additional support for
the structural biology program is provided by
the DOE
Office of Biological and Environmental Research, the NIH
National Center for Research Resources and the NIH Institute for General Medical
Sciences. Additional information about
SSRL and its operation and schedules is available from the SSRL WWW
site.
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