THEORY OF VIBRATIONAL MODE INTENSITIES IN INELASTIC ELECTRON-TUNNELING SPECTROSCOPY
THEORY OF VIBRATIONAL MODE INTENSITIES IN INELASTIC ELECTRON-TUNNELING SPECTROSCOPY
复制标题
DOI：
10.1103/physrevb.14.3177
复制
发表时间：
1976-01-01
影响因子：
3.7
通讯作者：
HANSMA, PK
中科院分区：
文献类型：
--
作者：
KIRTLEY, J;SCALAPINO, DJ;HANSMA, PK
我们使用一个转移哈密顿形式主义发展的非弹性电子隧穿光谱（IETS）的金属-绝缘体-金属结中的有机分子的振动模式的强度的理论。初始和最终的电子状态被定位在绝缘barier的相对侧上，并且由Wentzel-Kramers-Brillouin（WKB）波函数描述。隧穿电子和振动分子之间的相互作用势是库仑势的总和;总和中的每个元素对应于分子中原子上的部分电荷。该理论正确地预测了IETS中积分强度的大小以及相反偏置电压下的强度比。它还预测，拉曼活性模式的强度应该与红外模式相当，即使忽略键的极化率，并且在IETS中可以观察到光谱学禁止的模式。我们进一步描述了如何掺杂的分子在表面上的取向可以推断从IETS强度。
We use a transfer-Hamiltonian formalism to develop a theory for the intensity of vibrational modes in inelastic electron tunneling spectroscopy (IETS) of organic molecules in metal-insulator-metal junctions. The initial and final electron states are localized on opposite sides of the insulating barier and are described by Wentzel-Kramers-Brillouin (WKB) wave functions. The interaction potential between the tunneling electron and the vibrating molecule is a sum of Coulomb potentials; each element in the sum corresponding to a partial charge localized on an atom in the molecule. The theory predicts properly the magnitudes of the integrated intensities in IETS as well as the ratio of intensities for opposite bias voltages. It also predicts that Raman-active modes should be comparable in intensity to infrared modes, even neglecting bond polarizabilities, and that modes forbidden to optical spectroscopies may be observable in IETS. We further describe how the orientation of the doped molecules on the surface can be inferred from IETS intensities.