Evolution of local ordered domains in quenched 2D dusty plasma liquids

• Main Authors: Chi Yang, 楊基
• Other Authors: Lin I
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/76206328694385518119

碩士 === 國立中央大學 === 物理研究所 === 99 === The　micro-structure　and　micro-dynamics　of　glass-forming　liquids　are　interesting　and　important　issues.　The　dynamical　heterogeneity,　which　is　the　coexistence　of　cage　rattling　and　cage　jumping　of　particle,　and　its　structural　origin　have　attracted　much　attention　in　the　glass-forming　liquid.　It　is　also　found　that　the　structural　order　increases　with　the　increase　of　waiting　time　after　quenching,　resulting　in　the　formation　of　local　ordered　domains　separated　by　defect　clusters.　Furthermore,　the　particle　motions　become　strongly　correlated　due　to　the　suppression　of　thermal　agitation　at　low　temperature.　Instead　of　string-like　avalanche　cooperative　cage　jumping　in　liquid,　particles　can　affect　their　neighbors　and　form　band-like　motion　in　the　glass-forming　liquid.　However,　the　relation　between　the　evolution　of　local　ordered　domains　and　the　cooperative　particle　motions　is　still　elusive. In　this　work,　the　spatiotemporal　evolution　of　local　ordered　domains　and　structural　rearrangement　in　a　quenched　2D　dusty　plasma　liquid　formed　by　the　charged　dust　particles　suspended　in　a　low　pressure　argon　rf　discharge　are　experimentally　investigated　through　direct　optical　microscopy.　The　local　ordered　domains　are　identified　by　the　bond　orientational　order　of　particle.　The　collective　excitations　of　particles　are　classified　into　vortical　excitation,　elongation,　compression,　and　shear　motion　by　our　new　measurement　associated　with　the　effective　bond　connecting　pair　of　the　nearest　neighbor　particles.　It　is　found　that　the　local　ordered　domains　can　be　ruptured　by　the　small　spatial　scale　collective　excitations　of　particles.　Our　new　measurement　not　only　characterizes　the　collective　excitations　of　particles,　but　also　identified　the　spatial　distribution　of　local　strain　during　the　domain　evolution.　Finally,　the　mechanism　of　2D　structural　rearrangement　in　a　2D　quenched　liquid　is　explained　through　the　change　of　the　collective　excitations　of　particles.