In this work, we systematically study the electronic structure and stability of spin states of the [Fe-(tpy-ph)2]2+ molecule in both the gas phase and on a Au(111) substrate using density functional theory + U (DFT+U) calculations. We find that the stability of the Fe2+ ion's spin states predicted by the computations is significantly influenced by the Hubbard U parameter. In the gas phase, the low-spin (LS, S = 0) state is found to be energetically favorable for U(Fe) ≤ 3 eV, whereas the high-spin (HS, S = 2) state is stabilized for U(Fe) > 3 eV. Interaction with the Au(111) substrate is found to elevate the critical U for the spin-state transition to 3.5 eV. Additionally, we perform L-edge X-ray absorption spectroscopy (XAS) calculations for both HS and LS states. The calculated XAS suggests that the HS state more closely aligns with the experimental observations, indicating the potential coexistence of the HS state as the initial state during the X-ray excitation process. These findings enrich our understanding of spin-state dynamics in [Fe(tpy-Ph)2]2+.
Publications
2025
We report atomic-scale gating and visualization of local charge distribution within individual rare-earth-based molecular complexes on a metallic surface. The complexes are formed by a positively charged lanthanum ion coordinated to a (pcam)3 molecule and a negatively charged counterion trapped underneath via electrostatic interactions on a Au(111) surface. Local gating is performed by adding an additional negatively charged counterion to one side of the complex, which results in the redistribution of charges within the complex and a positive shift of the frontier orbitals. This is caused by the internal Stark effect induced by the added counterion. This effect is directly captured using tunneling spectroscopy and spectroscopic mapping at 5 K substrate temperature. The polarizability of the complex is corroborated by density functional theory and analytical calculations based on experimental findings. Furthermore, the influence of charge polarization on nearby complexes is investigated in a cluster purposely assembled using three complexes, which reveals maintaining the charge states as in single complexes. These findings will enable the design of robust charged rare-earth complexes to be tailored for potential solid-state applications.
2020
Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.
Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.
Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.
Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.
Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.
Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.
2019
Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.
Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.
Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.
Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.
Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.
Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.