有機染料在皮秒時域的質量傳輸效應研究

Study of picosecond pulse induced mass transport in organic dyes solution

曾建雲(Chien-Yun Tseng)

指導教授 ： 魏台輝

國立中正大學/理學院/物理學系/碩士(2015年)

摘要

摘要
本論文將有機染料鐵太青素(iron(III) Phthalocyanine-4,4',4'',4'''-tetrasulfonic acid，簡稱FePc)分別以兩種濃度溶於三種溶劑(H2O、D2O以及methanol)，然後以532 nm 18 picosecond (ps) 雷射脈衝為光源，用Z-scan技術來調查總計六種溶液中溶質分子的質量傳輸效應。由過去的研究，我們已知雷射脈衝的能量()須超過一臨界值(T)才可在某一溶液中造成溶質分子的質量傳輸效應，且對於相同溶劑，較低濃度樣品的T較低。
溶液樣品在熱力學平衡(thermodynamic equilibrium)狀態下，每一顆溶質分子被鄰近溶劑或溶質分子吸引力所造成的位能井(Lennard-Jones potential well)限制，僅能在其中往復振盪。類似地，每一顆溶劑分子也因鄰近溶質或溶劑分子所造成的位能井限制，僅能在其中往復振盪。如果我們能提供個別溶質分子超過T的能量，使溶質分子突破位能井的限制，則溶質分子將產生質量傳輸效應。針對相同的溶質分子與不同的的溶劑分子而言，溶質分子所感受到的位能井有不同的深度，因此脈衝能量需超過不同的臨界能量T始可對溶質分子產生質量傳輸效應。
本論文中我們調查溶劑與T的關係。實驗中，以極性分子鐵太青素(FePc)作為溶質，以及水、重水、甲醇作為溶劑，我們發現FePc分別溶於水、重水與甲醇中，雷射脈衝須提供逐次降低的臨界能量T造成溶質分子質量傳輸。

關鍵字

質量傳輸

並列摘要

Abstract
From previous Z-scan study of chloroaluminum phthalocyanine dissolved in ethanol (dubbed as ClAlPc-ethanol) with 19 picosecond (ps) laser pulses at 532 nm, with different pulse-to-pulse separation relative to the mass diffusion time, we have learned that each individual pulse carrying an energy exceeding a threshold T can induce the outward solute migration. This indicates that each ClAlPc molecule is confined within a Lennard-Jones Potential well formed by attractive forces of neighboring solvent and solute molecules when the solution is in full thermodynamic (thermal, mechanical and chemical) equilibrium.
Considering that the inter-molecular attractive forces may arise from the Van der Waals force or the hydrogen bonding, we conducted the same Z-scan measurements on an iron(III) Phthalocyanine-4,4',4'',4'''-tetrasulfonic acid (dubbed FePc) dissolved in three different solvents (DI water, Deuterium oxide and methanol) at two concentrations ( and ). This is to compare the inter-molecular attractive forces between FePc and the three solvents. As a result, we find water results in the deepest well for individual FePc molecules; DI water and methanol cause the second deepest and the shallowest wells for FePc. This is consistent with the order of polarity strength among the three solvents. It is more likely that the attractive forces between FePc and each solvent is more likely a kind of Van der waals force.

並列關鍵字

mass diffusion

參考文獻

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