| Summary: | 碩士 === 國立交通大學 === 應用化學系分子科學碩博士班 === 102 === For the past decade, we applied radiation pressure of an intense CW laser beam of 1064 nm to various kinds of amino acids such as glycine, proline, serine, etc, and succeeded in demonstrating their laser trapping-induced crystallization, as we named this phenomenon “Laser trapping crystallization”. Most recently, we also succeeded in laser trapping crystallization of L-phenylalanine (L-Phe) in H2O leading to the anhydrous crystal formation and explained that the anhydrous crystal formation was due to local laser heating over the transition point of 35-37°C.
In this thesis, I present pseudopolymorphism of L-Phe in D2O leading to monohydrate and anhydrous forms controlled by laser trapping. Different from the H2O solution, local temperature elevated by laser heating is too low to reach the transition point of L-Phe. Hence, the formation of anhydrous crystal was surely realized by laser trapping, and it was found that the formation probability strongly depends on solution concentration and laser polarization. The entire dynamics and mechanism is discussed in view of formation of cluster assembly characteristic under laser trapping and laser trapping-induced dehydration in the assembly depending on laser polarization.
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