Relaxation process of CO stretching mode of metal carbonyls adsorbed on Y zeolites studied by pump–probe experiment
Relaxation process of CO stretching mode of metal carbonyls adsorbed on Y zeolites studied by pump–probe experiment
复制标题
泵探针实验研究Y沸石吸附羰基金属CO拉伸模式的弛豫过程
DOI：
10.1063/1.476004
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
S. Kano
中科院分区：
文献类型：
--
作者：
K. Onda;M. Yaginuma;Toshiya Yokota;A. Wada;K. Domen;C. Hirose;S. Kano
利用皮秒红外激光脉冲，用泵浦探针法测定了Mo(CO)6和Cr(CO)6吸附在HY、DY和NaY分子筛笼中的振动弛豫寿命。HY、DY和NaY沸石上Mo(CO)6在110 K下v=1水平的寿命分别为70±4、53±5和150±9 ps， Cr(CO)6的寿命分别为87±6、74±7和140±12 ps。通过对110 K下的寿命和温度依赖性的比较表明，CO拉伸模式与四个接受模式的量子耦合决定了振动弛豫速率：(1)三种沸石体系中中心金属Cr或Mo的位移模式，(2)HY和DY沸石体系中沸石表面OH和OD基团的相关模式，以及(3)能量在300-800 cm−1的沸石框架振动模式。
The vibrational relaxation lifetimes of Mo(CO)6 and Cr(CO)6, adsorbed in a cage of HY, DY, and NaY zeolites, were measured at various temperatures by the pump–probe method using picosecond infrared laser pulses. The lifetimes at 110 K of the v=1 level of the CO stretching mode were 70±4, 53±5, and 150±9 ps for Mo(CO)6 on HY, DY, and NaY zeolite, respectively, and 87±6, 74±7, and 140±12 ps for Cr(CO)6, respectively. It was shown by comparison of the lifetimes at 110 K, as well as the temperature dependence, that the rate of vibrational relaxation is determined by the coupling of the CO stretching mode with four quanta of the accepting modes comprised of: (i) modes with displacement of central metals Cr or Mo in all of the three zeolite systems, (ii) modes associated with the OH and OD groups on zeolite surface in the HY and DY zeolite systems, and probably (iii) the frame vibrational modes of zeolite with energies at 300–800 cm−1.