Disentangling electronic and vibrational coherence in the Phycocyanin-645 light-harvesting complex

Abstract

Energy transfer between chromophores in photosynthesis proceeds with near unity quantum efficiency. Understanding the precise mechanisms of these processes is made difficult by the complexity of the electronic structure and interactions with different vibrational modes. Two-dimensional spectroscopy has helped resolve some of the ambiguities and identified quantum effects that may be important for highly efficient energy transfer. Many questions remain, however, including whether the coherences observed are electronic and/or vibrational in nature and what role they play. We utilise a two-colour four-wave mixing experiment with control of the wavelength and polarization to selectively excite specific coherence pathways. For the light-harvesting complex PC645, from cryptophyte algae, we reveal and identify specific contributions from both electronic and vibrational coherences and determine an excited state structure based on two strongly-coupled electronic states and two vibrational modes. Separation of the coherence pathways also uncovers the complex evolution of these coherences and the states involved.

References in corpus (7)

• Long-lived quantum coherence in photosynthetic complexes at physiological temperature
• Dephasing assisted transport: Quantum networks and biomolecules
• Environment-Assisted Quantum Transport
• Correlation-dependent coherent to incoherent transitions in resonant energy transfer dynamics
• Enhancement of Vibronic and Ground-State Vibrational Coherences in 2D Spectra of Photosynthetic Complexes
• Electronic excitation dynamics in multichromophoric systems described via a polaron-representation master equation
• Computational Methodologies and Physical Insights into Electronic Energy Transfer in Photosynthetic Light-Harvesting Complexes

Cited by in corpus (5)

• Energy transfer in structured and unstructured environments: master equations beyond the Born-Markov approximations
• Vibronic resonances facilitate excited state coherence in light harvesting proteins at room temperature
• Isolating quantum coherence with pathway-selective coherent multi-dimensional spectroscopy
• Multi-color quantum control for suppressing ground state coherences in two-dimensional electronic spectroscopy
• Beat-frequency-resolved two-dimensional electronic spectroscopy: disentangling vibrational coherences in artificial fluorescent proteins with sub-10-fs visible laser pulses