Excited
State Electronic Landscape of mPlum Revealed by Two-Dimensional Double
Quantum Coherence Spectroscopy
Patrick E. Konold
Ralph Jimenez
10.1021/jp5119772.s001
https://acs.figshare.com/articles/journal_contribution/Excited_State_Electronic_Landscape_of_mPlum_Revealed_by_Two_Dimensional_Double_Quantum_Coherence_Spectroscopy/2192257
Red
fluorescent proteins (RFPs) are widely used probes for monitoring
subcellular processes with extremely high spatial and temporal precision.
In this work, we employed spectrally resolved transient absorption
(SRTA) and two-dimensional double quantum coherence (2D2Q) spectroscopy
to investigate the excited state electronic structure of mPlum, a
well-known RFP. The SRTA spectra reveal the presence of excited state
absorption features at both the low- and high-energy sides of the
dominant ground state bleach contribution. The 2D2Q spectra measured
at several excitation wavelengths reveal a peak pattern consistent
with the presence of more than three electronic states (i.e., ground,
excited, and doubly excited). Numerical modeling of this response
suggests that the features are consistent with a 1–1–2
electronic structure. The two closely spaced (∼1500 cm<sup>–1</sup>) levels in the double quantum manifold appear at
opposite anharmonicities relative to twice the energy of the lowest
energy transition. These observations explain the excited state absorption
contributions observed in spectrally resolved transient grating and
transient absorption measurements and demonstrate the utility of multidimensional
spectroscopy in unraveling congested spectra relative to conventional
one-dimensional methods.
2015-02-26 00:00:00
presence
energy transition
ground state bleach contribution
monitoring subcellular processes
2 D 2Q spectra
peak pattern
SRTA spectra
excitation wavelengths
quantum manifold
RFP
absorption measurements
Excited State Electronic Landscape
mPlum Revealed
state absorption contributions
Numerical modeling
state absorption features
spectroscopy