ELECTRONIC SPECTROSCOPY OF FUV-IRRADIATED DIAMONDOIDS: A COMBINED EXPERIMENTAL AND THEORETICAL STUDY
ELECTRONIC SPECTROSCOPY OF FUV-IRRADIATED DIAMONDOIDS: A COMBINED EXPERIMENTAL AND THEORETICAL STUDY
复制标题
FUV 辐照金刚石的电子光谱：实验和理论相结合的研究
DOI：
--
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
T. Henning
中科院分区：
文献类型：
--
作者：
M. Steglich;F. Huisken;J. Dahl;R. Carlson;T. Henning
用高能光子(10.2-11.8 eV)对分离于固体稀有气体基质中的小钻石进行低温辐照。通过紫外吸收光谱对光产物进行了示踪。我们发现，在电离时，这些物种中最小的一个失去了一个外围的H原子，形成了一个稳定的闭壳阳离子。这一过程也可能发生在气相钻石类化合物的天体物理条件下，由于脱氢阳离子具有强大的永久偶极矩，因此它开启了利用旋转光谱检测类钻石分子的可能性。这些物种在紫外光中的最低能量电子特征被发现是相当广泛的，随着分子尺寸的增加而向更长的波长移动。用含时密度泛函理论计算支持了我们的实验结果，并将吸收曲线进一步扩展到真空紫外区。完整的σ-σ*光谱显示出惊人的相似之处，与含有50倍以上C原子的陨石纳米钻石相似。
Irradiation with high-energy photons (10.2–11.8 eV) was applied to small diamondoids isolated in solid rare gas matrices at low temperature. The photoproducts were traced via UV absorption spectroscopy. We found that upon ionization the smallest of these species lose a peripheral H atom to form a stable closed-shell cation. This process is also likely to occur under astrophysical conditions for gas phase diamondoids and it opens the possibility of detecting diamond-like molecules using their rotational spectrum since the dehydrogenated cations possess strong permanent dipole moments. The lowest-energy electronic features of these species in the UV were found to be rather broad, shifting to longer wavelengths with increasing molecular size. Calculations using time-dependent density functional theory support our experimental findings and extend the absorption curves further into the vacuum ultraviolet. The complete σ–σ* spectrum displays surprisingly strong similarities to meteoritic nanodiamonds containing 50 times more C atoms.