How is the Hydrodynamic Diameter defined?

Q: How is the Hydrodynamic Diameter defined?

The hydrodynamic diameter (D h ) of a molecule is defined as the diameter of a perfect solid sphere that would exhibit the same hydrodynamic friction as the molecule of interest. Thus, the D h value reflects primarily the hydrodynamic friction but is usually also a good estimation of the absolute size of the molecule. Generally, the more globular the shape of a molecule is, the better the D h value reflects the actual diameter.

Question

Bogdan Dochia · Accepted Answer

The hydrodynamic diameter (D_h) of a molecule is defined as the diameter of a perfect solid sphere that would exhibit the same hydrodynamic friction as the molecule of interest. Thus, the D_h value reflects primarily the hydrodynamic friction but is usually also a good estimation of the absolute size of the molecule. Generally, the more globular the shape of a molecule is, the better the D_h value reflects the actual diameter.