Question
Samples in this technique are mounted on a goniometer prior to being bombarded with light to form an interference pattern. For 10 points each:
[10e] Name this technique that measures the diffraction of high-energy light to determine the structure of macromolecules. Photo 51 was obtained by Rosalind Franklin using this technique.
ANSWER: X-ray crystallography [or X-ray diffraction; or XRD; prompt on crystallography or diffraction]
[10m] Patterson functions are used to solve a “problem” named for this quantity that arises because CCDs in X-ray crystallography machines only measure intensity. A form of this quantity named for Michael Berry causes the Aharonov–Bohm effect.
ANSWER: phase [accept phase problem or Berry phase]
[10h] Once the phase problem has been corrected, chemists can calculate how well their predictions match a chemical’s actual structure using this parameter. This parameter quantifies the differences between the observed and calculated structure factors.
ANSWER: R-factor [or residual factor or reliability factor or the R-value or RWork]
<Chemistry>
Summary
| 2024 ACF Regionals @ Berkeley | 01/27/2024 | Y | 1 | 20.00 | 100% | 100% | 0% |
| 2024 ACF Regionals @ JMU | 01/27/2024 | Y | 1 | 0.00 | 0% | 0% | 0% |
| 2024 ACF Regionals @ JMU | 01/27/2024 | Y | 1 | 20.00 | 100% | 100% | 0% |
| 2024 ACF Regionals @ Nebraska | 01/27/2024 | Y | 6 | 11.67 | 83% | 33% | 0% |
| 2024 ACF Regionals @ Imperial | 01/27/2024 | Y | 8 | 15.00 | 100% | 38% | 13% |
| 2024 ACF Regionals @ Vanderbilt | 01/27/2024 | Y | 1 | 20.00 | 100% | 100% | 0% |
| 2024 ACF Regionals @ MIT | 01/27/2024 | Y | 3 | 10.00 | 33% | 33% | 33% |
Data
| Maryland C (DII) | Liberty B (DII) | 0 | 0 | 0 | 0 |
| UNC B (UG) | Maryland A (Grad) | 10 | 10 | 0 | 20 |