Control of Resonance Transitions of Substances Encapsulated in Fullerenes by Using Synchrotron Radiation

(1)用飞行时间质谱仪测量了一种面内金属富勒烯M@C_&lt；82&gt；(M=Ce，Pr)在100-150 eV光子能量范围内的光离子产额谱。在质谱图中观察到母离子M@C&lt；82&gt；+，M@C&lt；82&gt；+和M@C&lt；82&gt；3+&gt；M@C&lt；82&gt；^&lt；2+&gt；的光离子产额谱在120-140 eV处有一个宽峰，归属于包裹金属原子的4d-4f巨偶极共振。从离共振和开共振位置的光离子产额谱估算了M@C&lt；82&gt；的绝对光吸收截面。(2)发展了一种利用速度图成像法观测快分子束速度分布的新技术。用该技术观测了富勒烯C_(60)&gt；分子束的光离子图像。在图像的中心有一个狭窄而强烈的图案，主要源于C_&lt；60&lt；2+&gt；。(3)用光子衰减法测定了C&lt；60&gt；薄膜在1.3-42 eV范围内的绝对光吸收截面。光谱显示在22.1 eV处有一个1180Mb的显著峰，与气相中的C&lt；60&gt；类似，由于单电子激发，有几个精细结构。通过Kramers-Kronig分析计算了高达42 eV的复折射率和复介电函数。根据现有的C_(60)薄膜数据，在假设C_(60)分子的极化效应可以用Clausius-Mossotti关系表示的前提下，计算了C_(60)分子的截面曲线。所得光谱与C_(60)和C_(60)在气相中的光谱符合得很好。

(1) The photoion yield spectra of an endohedral metallofullerene M@C_<82> (M=Ce, Pr) were measured in the photon energy range of 100-150 eV by using time-of-flight mass spectrometry. Parent ions, M@C_<82>+, M@C_<82>+ and M@C_<82>^<3+> were observed in the mass spectra. The photoion yield spectra of M@C_<82>^<2+> showed a broad peak at 120-140 eV that was assigned to the 4d-4f giant dipole resonance of the encapsulated metal atoms. Absolute photoabsorption cross sections of M@C_<82> were evaluated from the photoion yield spectra at off- and on-resonance positions.(2) A new technique has been developed for observing the velocity distribution of a fast molecular beam by making use of a velocity map imaging method. The photoion images of fullerene C_<60> molecular beams were observed with this technique. At the center of the image there is a narrow and intense pattern which stems mainly from C_<60>^<2+>. The temperature of the neutral beam evaluated from the images agrees well with that of the hot oven containing C. sample powder.(3) Absolute photoabsorption cross sections of C_<60> thin films are determined in the hv range from 1.3 to 42 eV by using photon attenuation method. The spectrum shows a prominent peak of 1180 Mb at 22.1 eV with several fine structures due to single-electron excitation similarly to the case of C_<60> in the gas phase. The complex refractive index and complex dielectric function are calculated up to 42 eV through the Kramers-Kronig analyses. From the present data of C60 thin films the cross section curve of a molecular C_<60> is calculated with an assumption that the polarization effect of surrounding C_<60> molecules can be expressed by the Clausius-Mossotti relation. The spectrum thus obtained shows an excellent agreement with that of C_<60> in the gas phase.