Skip to main content

Computational and FTIR Spectroscopic Studies of Vibrational and Electronic Properties of Transition Metal Mixed-Valence Complexes in Solution

EMSL Project ID


Developing a detailed molecular picture of ultrafast photoinduced electron transfer processes in solution will aid the development of new light harvesting technologies. The goal of this project is to obtain a detailed characterization of the ground and excited electronic-state properties of a series of transition metal mixed-valence metal complexes, [(CN)5MII-CN-MIII(NH3)5]- where M = Fe, Ru. These molecules are characterized by an intense metal-to-metal charge transfer excitation at visible wavelengths. This transition is strongly coupled to the CN vibrational modes in these molecules. Consequently, these are ideal model systems in which to understand the interplay of electronic and nuclear degrees of freedom during photoinduced charge transfer in solution. Ultrafast spectroscopies are being used to study these molecules, and the current proposal will compliment these studies with computational and spectroscopic investigations. The use of EMSL's unique computing and experimental facilities are proposed. Computer time on the Chinook supercomputer will be used to study these molecules in real solution environments. The hybrid quantum-classical approaches available in NWChem will be used to provide a realistic description of the solvent structure around these molecules. Density functional and coupled-cluster theories will be employed to describe the solute molecules while the solvent will be treated classically. This will allow the rigorous investigation of vibrational and electronic properties of these molecules in realistic environments. In the course of this project, the vibrational property module of NWChem will be extended to aid the investigation. EMSL's Fourier transform infrared spectrometer (FTIR) will be used to gather the far-IR (20 to 400 cm-1) low-frequency spectra of these molecules. Low-frequency modes in these systems govern energy transfer pathways that regulate the dissipation of energy following a photochemical event. By understanding the low-frequency spectrum of these molecules, the couplings between high and low-frequency modes will be determined. Together these computational and experimental studies will provide a detailed molecular picture that provides an ideal context for studying photoinduced electron transfer.

Project Details

Project type
Exploratory Research
Start Date
End Date


Principal Investigator

Munira Khalil
University of Washington

Team Members

Benjamin Van Kuiken
University of Washington

Kenneth Lopata
Louisiana State University

Niranjan Govind
Pacific Northwest National Laboratory

Marat Valiev
Environmental Molecular Sciences Laboratory

Related Publications

Van Kuiken BE, M Valiev, SL Daifuku, C Bannan, ML Strader, H Cho, N Huse, RW Schoenlein, N Govind, and M Khalil. 2013. "Simulating Ru L3-edge X-ray Absorption Spectroscopy with Time-Dependent Density Functional Theory: Model Complexes and Electron Localization in Mixed-Valence Metal Dimers." Journal of Physical Chemistry A 117(21):4444-4454.