테트라메틸암모늄 퍼클로레이트(Tetramethylammonium perchlorate)의 압력변화에 따른 구조변이 및 분자거동에 관한 연구

Abstract

Tetramethylammonium perchlorate (TMAP) is a [(CH3)4N]+ salt containing [ClO4]- as a counter ion. TMAP has the tetragonal crystal system at room temperature, and it undergoes a structural phase transition to the orthorhombic crystal system at the low temperature under 150 K (Papacios, 2003). The crystal structure of TMAP with such a character was determined by X-ray diffraction under an ultra high pressure condition of up to 8.5 GPa created using the diamond anvil cell, and the result clearly showed that TMAP that had the tetragonal system at the pressure under 2 GPa underwent the structural phase transition to the orthorhombic system. In order to determine the molecular motion within the TMAP crystal at the ultra high pressure, x-ray diffraction data were analyzed and visualized into images using the Generalized Structure Analysis System (GSAS).