X-ray crystallography - Upstate NY

Question

Incomplete measurements from CCDs in this technique can lead to a loss of information called the “phase problem.” For 10 points each:

[10e] Name this technique that uses low-wavelength light to probe lattice structures. Rosalind Franklin used this technique to determine the structure of DNA.

ANSWER: X-ray crystallography [or X-ray diffraction or XRD]

[10m] X-ray crystallography is limited in scale by the diffraction limit for this quantity usually measured in angstroms. A coefficient of 1.22 appears in the Rayleigh criterion for this quantity.

ANSWER: resolution [accept angular resolution; accept resolving power; prompt on angle]

[10h] Molecular modelling using X-ray crystallography uses this quantity defined by summing differences in structure factors over all reflections. A “free” form of this quantity is usually one tenth the resolution.

ANSWER: R-factor [or R-value; accept R-free; accept discrepancy index]

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Summary


California	2025-02-01	Y	3	13.33	100%	33%	0%
Florida	2025-02-01	Y	2	25.00	100%	100%	50%
Lower Mid-Atlantic	2025-02-01	Y	6	10.00	83%	0%	17%
Midwest	2025-02-01	Y	6	10.00	100%	0%	0%
North	2025-02-01	Y	3	13.33	67%	33%	33%
Northeast	2025-02-01	Y	5	14.00	100%	20%	20%
Overflow	2025-02-01	Y	5	20.00	100%	40%	60%
South Central	2025-02-01	Y	2	20.00	100%	100%	0%
Southeast	2025-02-01	Y	4	12.50	100%	0%	25%
UK	2025-02-01	Y	10	13.00	100%	30%	0%
Upper Mid-Atlantic	2025-02-01	Y	8	16.25	88%	63%	13%
Upstate NY	2025-02-01	Y	3	10.00	100%	0%	0%

Data


Cornell D	Binghamton A	10	10
ESF A	RIT A	10	10
Cornell C	RIT B	10	10