Crystal Nucleation by Laser-Induced Cavitation

详细信息    查看全文

• 作者：Anamaria Soare ; Rory Dijkink ; Marcos Rodriguez Pascual ; Chao Sun ; Peter W. Cains ; Detlef Lohse ; Andrzej I. Stankiewicz ; Herman J. M. Kramer
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：June 1, 2011
• 年：2011
• 卷：11
• 期：6
• 页码：2311-2316
• 全文大小：854K
• 年卷期：v.11,no.6(June 1, 2011)
• ISSN：1528-7505

文摘

High-speed and high-resolution photography have been used to investigate the relationship between creation, expansion, and collapse of a vapor cavity induced by a 6 ns laser pulse and the subsequent nucleation of crystals. A thin layer of supersaturated aqueous solutions of (NH₄)₂SO₄ and KMnO₄ was confined between two glass plates with a separation of 50 and 100 渭m. The expansion and collapse of the laser-induced vapor bubble occurred over a total time scale of 200 渭s, while the first identifiable crystal appears one second after the laser pulse. Crystals were observed to form on a ring with a diameter of 70 渭m centered in the focal point of the laser. The ring is preceded by an optical disturbance observed through the cavity around 30鈥?0 渭s after the laser pulse and vapor cavity formation. This ring-shaped optical disturbance originates from changes in refractive index induced by crystal nuclei formation. The formation of the nuclei most probably coincides with the formation of the bubble, when the rate of evaporation and the supersaturation are at their maxima. Apparently, it takes the nuclei around 30鈥?0 渭s to grow to a particle size with a visible optical disturbance.