Ice Nucleation by Metaldehyde

Abstract

DURING recent years ice-nucleation by some organic substances has been investigated with increasing interest in fundamental, as well as in practical, fields. Some steroids can nucleate ice crystals at temperatures as high as − 1° C when prepared by thermal recrystallization^1,2. One of the amino-acids³ is reported to nucleate ice at − 4.5° C. Although many of them have complicated molecular and crystal structures and are not common, they may be useful in understanding heterogeneous ice-nucleation. For application to cloud-seeding, phloro-glucinol⁴, α-phenazine⁵ and a few others have been found among the common organic compounds to overcome the faults of silver iodide as a practical seeding material, such as photolytic inactivation and high price. The wide variety of organic compounds gives some hope of finding improved cloud-seeding materials.