六同多钨酸阴离子的振动光谱

本文观测了六同多钨酸阴离子的红外和喇曼光谱, 并用MUBFF、UBFF和GVFF三种力场对W_6O_(19)~(2-)的振动作了简正坐标分析。得到了力常数、振动频率和振动势能分布。对振动频率作出归属, 讨论了力常数间的关系, 给出了用MUBFF的计算结果。

ANALYSIS OF VIBRATIONAL SPECTRA FOR ISOHEXAPOLYTUNGSTATE ANION

Infrared and Raman spectra of W_6O_(19)~(2-) were measured, and the normal coordi- nate analysis was performed for the W_6O_(19)~(2-) anion by using general valence force field (GVFF), Urey-Bradley force field (UBFF) and modified Urey-Bradley force field (MUBFF). The later is the best one,and the result is given. The sym- metrical coordinates consisted of 132 internal coordinates were used, in order to split the secular equations into blocks and assign the symmetrical species of the vibrations. For the terminal oxygen exhibit stronger electric negativity, repulsive forces among them were considered in MUBFF, and an improved result was obtained at high wavenumbers. Although the central oxygen atom exhibits ion character, the contributions of the internal coordinates associated with it should not be ignored. However, these coordinates only show an effect on IR active bands, and so Raman active bands 230 cm~(-1) (A_(1g)) and 122 cm~(-1) (E_g) can′t be assigned as W-O_c stretching. Moreover, the Raman band 122 cm~(-1) assigned as F_(2g) was found following the prediction of the calculation.