| STUDY |
Using short pulses of light to probe crystallization in solutions, scientists have demonstrated that polarized laser radiation can steer crystallization toward one polymorphic form over another. The new procedure for controlling crystallization may provide researchers with a means for selecting among the forms in which a compound crystallizes. The study broadens understanding of crystallization mechanisms, which are essential to industrial chemical processes such as separation and purification. The work builds on earlier studies in which the team showed that linearly polarized light causes urea to nucleate in a few nanoseconds instead of a few days, and in such a way that the needle-shaped crystals tend to align with their needle axes parallel to the laser light's electric field direction. The group proposes that nucleation occurs through electric-field-induced alignment of the molecules |
| COMMENTS | Unlike much of the previous work in the field, in which crystal nucleation is induced via photochemical processes, "the present experiment shows conclusively that an entirely different mechanism is possible," says University of Chicago chemistry professor David W. Oxtoby. "This could be of importance in materials science and pharmaceutical chemistry where various crystalline forms of a substance can have entirely different physical, chemical, and biological properties |
| UPDATE | 10.02 |
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