Temperature value: Difference between revisions
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The B-factor is given<ref name="rcampbell" /> by | The B-factor is given<ref name="rcampbell" /> by | ||
<center><span style="font-size:150%">B<sub>i</sub> = 8π<sup>2</sup>U<sub>i</sub><sup>2</sup></span></center> | <center><span style="font-size:150%">B<sub>i</sub> = 8π<sup>2</sup>U<sub>i</sub><sup>2</sup></span></center> | ||
where U<sub>i</sub><sup>2</sup> is the mean square displacement of atom i. As U increases, the B-factor increases and the contribution of the atom to the scattering is decreased. If atoms are incorrectly positioned in the model, their B-factors will tend to be higher than correctly positioned atoms nearby<ref name="rcampbell" />. For a B-factor of 15 Å<sup>2</sup>, the mean square displacement of an atom from its equilibrium position is approximately 0.44 Å, and approximately 0.87 Å for a B-factor of 60 Å<sup>2</sup>. | where U<sub>i</sub><sup>2</sup> is the mean square displacement of atom i. As U increases, the B-factor increases and the contribution of the atom to the scattering is decreased. If atoms are incorrectly positioned in the model, their B-factors will tend to be higher than correctly positioned atoms nearby<ref name="rcampbell" />. For a B-factor of 15 Å<sup>2</sup>, the mean square displacement of an atom from its equilibrium position is approximately 0.44 Å, and approximately 0.87 Å for a B-factor of 60 Å<sup>2</sup>. For comparison, the van der Waals ''diameter'' of a carbon atom is 3.9 Å. | ||
==Disorder== | ==Disorder== | ||
