Advanced Crystallography
NSF’s ChemMatCARS – Advanced Crystallography program is dedicated to small-molecule single-crystal X-ray diffraction. The diffractometers are pre-aligned internally, allowing them to be quickly moved into the beam as needed. This flexibility provides the ability to take advantage of beam availability on short notice, a capability that has been extensively utilized in user experiments.
The facility features a “rapid setup” system, enabling quick transitions to the single-crystal instrument.
Available Techniques & Instruments:
Resonance Diffraction/Diffraction Anomalous Fine Structure (DAFS)
Resonant diffraction/Diffraction Anomalous Fine Structure (DAFS) is a powerful technique for identifying specific elements at designated crystallographic sites. DAFS works by mapping the absorption spectrum through varying X-ray energies during single-crystal diffraction to identify the element’s oxidation state. These applications can only be conducted at synchrotron light sources.
Structural Dynamics
Structural Dynamics is exploring molecular structure in “non-equilibrium states” and “real environment”.
- Photo- or time-resolved crystallography uses the pulsed nature of the synchrotron source, together with its brilliance, to measure diffraction from samples that have been raised to excited states using laser light.
- In-situ structural dynamics experiments use an in-house design Environmental Control Cell (ECC) to study the confirmation of molecular structure changes under the real environmental conditions, such as gas, vacuum, solutions, and humidity.
- 3D Delta Pair Distribution Function – Study disorder from order
High-Resolution Charge Density Studies
High resolution charge density (HRCD)
- Calculate Intermolecular interaction energy
- Calculate the electric static potential of the molecule
- Bonding information (topological analysis and source function analysis)
- Characterization of the H-BOND
- Determine the atomic charge using Atom in Molecular Theory(AIM)
- Extract the “experimental wave function”
Under Extreme Conditions
- High-Pressure Studies:
- Chemical high-pressure crystallography (<10GPa) using Diamond Anvil Cell (HPDAC)
- Measurement of compression
- Characterization of phase transitions
- Variable temperature (10K-700K)
- Combined variable pressures and temperatures to characterize the phase diagram
Microcrystallography
Microcrystallography provides:
- Routine service crystallography on micro-crystals that cannot be measured elsewhere
- Fast data collection (10 minutes) and good for air sensitivity compounds
- Variable temperature (10k-700k)
- Mail-in Service
Experiment Specifications
- Monochromators 15-ID-1
- Si (111): energy range, 5 – 32 KeV
- Si (311): energy range, 10 – 70 KeV
- Multilayers: 20KeV (3nm, bandwidth 1.3%) & 30 KeV (2nm, bandwidth 0.85%)
- Monochromator 15-ID-2
- Si (111): energy range, 3.5 – 13.6 KeV
- Si (220): energy range, 5.7 – 22.2 KeV
- Si (440): energy range, 8.1 – 31.5 KeV
- Diffractometer Type:
- 15-ID-B:
- Huber 4-circle
- SmartGon
- Alio diffractometers
- 15-ID-D:
- Huber 3-circle
- Roadrunner diffractometers
- 15-ID-B:
- Detectors:
- Dectris Pilatus3 X 2M (Si 1mm)
- Dectris Pilatus3 X 1M (CdTe)
- Dectris Pilatus4 XE 2M(CdTe)
- Vortex Detector
- Software: APEX3/4/5 suite, HPUtility, AmaskDectris, TOPAS
- Sample Environment:
- Custom-made X-ray Chopper – Jülich chopper
- Cryojet N2 cold stream (90 – 300 K temperature range)
- Open-flow liquid He cryostat (10 – 70 K temperature range)
- Open-flow liquid N2 heat gun (300 – 700 K)
- Diamond Anvil Cell (DAC)- with 85° and 120° opening
- Environmental Control Cell (ECC)
- Oxford Cryostream 1000 Plus LN2 (90- 500K)
- Oxford Cryostream N-Helix Helium (30-300K)
- Spectrometer UV-VIS-NIR light source
Crystallography Contacts
Yu-Sheng Chen
(630) 252-0471
yushengchen@uchicago.edu
Tieyan Chang
(630) 252-5882
tychang@uchicago.edu
