Studies on the dynamic behavior of quasi-liquid layers on ice crystal surfaces by advanced optical microscopy

2014 Fiscal Year Final Research Report

• Project/Area Number: 23246001
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied materials science/Crystal engineering
• Research Institution: Hokkaido University
• Principal Investigator: SAZAKI GEN 北海道大学, 低温科学研究所, 教授 (60261509)
• Co-Investigator(Kenkyū-buntansha): FURUKAWA Yoshinori 北海道大学, 低温科学研究所, 特任教授 (20113623) ; NAGASHIMA Ken 北海道大学, 低温科学研究所, 助教 (60436079) ; MURATA Ken-ichiro 北海道大学, 低温科学研究所, 助教 (60646272)
• Research Collaborator: ASAKAWA Harutoshi 北海道大学, 低温科学研究所, 博士研究員 ; KIYOTA Tatsuo 北海道大学, 大学院理学研究科宇宙理学専攻 ; INOMATA Masahiro 北海道大学, 大学院理学研究科宇宙理学専攻
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: 氷 / 表面融解 / 疑似液体層 / 単位ステップ / 高分解光学顕微法

Outline of Final Research Achievements

We first devised an observation chamber in which temperature of sample ice crystals and supersaturation of water vapor can be controlled separately. Then we obtained the following five findings. 1) Only under supersaturated condition (higher than a critical value), two types of quasi-liquid layer (QLL) phases with drop and thin-layer shapes are formed on ice basal faces. 2) Strain formed around lattice defects in ice crystals significantly induces the formation of the two QLL phases. 3) On prism and other high-index faces, the two QLL phases with the drop and thin-layer shapes are also formed in the temperature ranges similar to those on basal faces. 4) Volume diffusion (in a bulk gas phase) and surface diffusion (on basal faces) of water vapor molecules govern the lateral advancement rate of elementary steps on ice basal faces. 5) On basal faces, spiral steps formed by screw dislocations exhibit a double-spiral structure because of a crystallographic requirement.

Free Research Field

雪氷の結晶成長