Mapping the excited states of single hexa-peri-benzocoronene oligomers.
Mapping the excited states of single hexa-peri-benzocoronene oligomers.
复制标题
绘制单一六邻苯并苯低聚物的激发态图。
作者：
W. Soe;H. S. Wong;C. Manzano;M. Grisolía;M. Hliwa;Xinliang Feng;K. Müllen;C. Joachim
分子的电子态通常是通过由单电子分子轨道建立的多电子斯莱特行列式的线性叠加分解来分析的。通常认为，扫描隧道显微镜（STM）能够绘制这些分子轨道。利用低温超高真空（LT-UHV）扫描隧道显微镜（STM），记录了六苯并蔻（HBC）单体、二聚体、三聚体和四聚体的dI/dV电导图。我们证明了将隧道电子共振归因于STM结中分子的特殊π分子轨道（或σ单体间化学键）是不恰当的。与STM弱测量类似的程序，dI/dV共振的结果，从电导贡献的许多分子状态的叠加使得很难重建一个表观分子轨道电子概率密度图。
Electronic states of a molecule are usually analyzed via their decomposition in linear superposition of multielectronic Slater determinants built up from monoelectronics molecular orbitals. It is generally believed that a scanning tunneling microscope (STM) is able to map those molecular orbitals. Using a low-temperature ultrahigh vacuum (LT-UHV) STM, the dI/dV conductance maps of large single hexabenzocoronene (HBC) monomer, dimer, trimer, and tetramer molecules were recorded. We demonstrate that the attribution of a tunnel electronic resonance to a peculiar π molecular orbital of the molecule (or σ intermonomer chemical bond) in the STM junction is inappropriate. With an STM weak-measurement-like procedure, a dI/dV resonance results from the conductance contribution of many molecular states whose superposition makes it difficult to reconstruct an apparent molecular orbital electron probability density map.