POLYENE SPECTROSCOPY - PHOTOELECTRON-SPECTRA OF DIPHENYLPOLYENES
POLYENE SPECTROSCOPY - PHOTOELECTRON-SPECTRA OF DIPHENYLPOLYENES
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DOI：
10.1021/ja00421a013
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发表时间：
1976-01-01
影响因子：
15
通讯作者：
DIAMOND, J
中科院分区：
文献类型：
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作者：
HUDSON, BS;RIDYARD, JNA;DIAMOND, J
在6 ~ 20 eV范围内，获得了二苯基多烯芪、二苯基丁二烯、二苯基己三烯、二苯基辛四烯、二苯基十五烯、二苯基十二碳六烯和二苯基十六碳八烯（Ph-f=-）-，，Ph = 1，2，3，4，5，6和8）的光电子能谱。这些光谱的相似性允许对电离峰进行经验分类，即，那些与链长无关的峰和那些随着链长增加而移动到较低能量的峰。与链长无关的峰位于9.1、11.4和14.2 eV处，并被鉴定为苯基电离。能量随链长变化的峰被确定为主要是多烯链电离的苯环的小系数的轨道。对于具有1、2、3、4、5、6和8个双键的多烯，最低电离能分别出现在7.94、7.56、7.33、7.19、7.05、7.07和7.2eV左右，表明在长链长度下，电离能趋于一个恒定值。这种行为让人想起二甲基多烯的激发能的收敛。对整个系列进行了Hiickel分子轨道处理，并用填充的MO能级鉴定了电离峰。调整两个参数a和b以拟合22个指定的过渡，得到以下值：|）= 6.32±0.04 eV，以及|0o| = 2.80±0.04 eV，计算值与实测值的标准偏差为0.07 eV，与实验误差基本一致。该协议同样适用于高能量和低能量。
Photoelectron spectra in the region from 6 to 20 eV have been obtained for the diphenylpolyenes stilbene, diphenyl-butadiene, diphenylhexatriene, diphenyloctatetraene, diphenyldecapentaene, diphenyldodecahexaene, and diphenylhexadecaoctaene, Ph-f=-)-,, Ph,= 1, 2, 3, 4, 5, 6, and 8. The similarity of these spectra allows an empirical classification of the ionization peaks to be made, namely, those which are independent of chain length and those which move to lower energy as the chain length increases. The peaks which are independent of chain length are at 9.1, 11.4, and 14.2 eV and are identified as phenyl group ionizations. The peaks which change energy with chain length are identified as predominantly polyene chain ionizations from orbitals with small coefficients for the phenyl rings. The lowest energy ionizations occur at 7.94, 7.56, 7.33, 7.19, 7.05, 7.07, and about 7.2 eV for thepolyenes with 1, 2, 3, 4, 5, 6, and 8 double bonds, indicating a convergence to a con-stant value at long chain length. This behavior is reminiscent of the convergence of the excitation energies of the dimethyl-polyenes. A Hiickel molecular orbital treatment of the entire series was performed, and the ionization peaks were identified with filled MO energy levels. Adjustment of the two parameters a and ß to fit 22 assigned transitions gave values of|)= 6.32±0.04 eV and| 0o|= 2.80±0.04 eV with a standard deviation between calculated and observed points of 0.07 eV which is approximately equalto the experimental error. The agreement is equally good at high and low energies.