铁观音茶叶激光诱导等离子体特性研究

Study on the Characteristics of Laser-Induced Plasma in Tieguanyin Tea

中国是茶的故乡和发源地,如今茶文化已经传播到世界各地,茶叶是仅次于水的第二大饮料。本文应用激光诱导击穿光谱(LIBS)技术对铁观音茶叶的元素组成进行了研究,发现铁观音茶叶含有Ca、Na、Mg、K、Fe、Cu、Zn、Mn、Sr、Al、Li和Ba等元素,同时还探测到了CN和C2分子的谱线。其次,对激光诱导下铁观音茶叶产生的等离子体特性进行了研究,通过对Hα谱线进行洛伦兹拟合获得电子数密度(Ne)为1.44 × 1017 cm−3,建立Saha-Boltzmann图,计算得等离子体温度(T)为8161 K。最后,使用LIFBASE软件对CN ( △v=0)分子进行模拟,获得振动温度(Tv)和转动温度(Tr)分别为6800 K和5800 K,且这三个温度在实验中满足关系T > Tv > Tr,这个关系与等离子体随时间演化的实际情况相符。

China is the hometown and birthplace of tea. Nowadays, tea culture has spread to all over the world and tea is the second largest beverage after water. In this study, the elemental composi-tion of Tieguanyin tea was studied by laser-induced breakdown spectroscopy (LIBS). Ca, Na, Mg, K, Fe, Cu, Zn, Mn, Sr, Al, Li and Ba were found in Tieguanyin tea. The spectral lines of CN and C2 were also detected. Then, the plasma characteristics of Tieguanyin tea of laser-induction were researched. The electron density (Ne) was 1.44 × 1017 cm−3 by using the Lorentz fitting of the Hα line. The Sa-ha-Boltzmann plot was established, and the plasma temperature (T) was calculated to be 8161 K. Finally, LIFBASE software was used to simulate CN ( △v=0 ) molecule, and the vibration tempera-ture (Tv) and rotation temperature (Tr) were obtained as 6800 K and 5800 K, respectively. In the experiment, the three temperatures met the relationship T > Tv > Tr, which was consistent with the actual situation of plasma evolution over time.