The non-radiative relaxation of the excitation energy from higher energy states to the lowest energy state in chlorophylls is a crucial preliminary step for the process of photosynthesis. Despite the continuous theoretical and experimental efforts to clarify the ultrafast dynamics of this process, it still represents the object of an intense investigation because the ultrafast timescale and the congestion of the involved states makes its characterization particularly challenging. Here we exploit 2D electronic spectroscopy and recently developed data analysis tools to provide more detailed insights into the mechanism of internal conversion within the Q-bands of chlorophyll a. The measurements confirmed the timescale of the overall internal conversion rate (170 fs) and captured the presence of a previously unidentified ultrafast (40 fs) intermediate step, involving vibronic levels of the lowest excited state.

Infrared spectroscopyo fl iquid biopsies is at imeand cost-effective approach that may advance biomedical diagnostics.H owever,t he molecular nature of disease-related changes of infrared molecular fingerprints (IMFs) remains poorly understood, impeding the methodsa pplicability.H ere we probe 148 human blood sera and reveal the origin of the variations in their IMFs.Tothat end, we supplemented infrared spectroscopyw ith biochemical fractionation and proteomic profiling,p roviding molecular information about serum composition. Using lung cancer as an example of am edical condition, we demonstrate that the disease-related differences in IMFs are dominated by contributions from twelve highly abundant proteins-that, if used as ap attern, may be instrumental for detecting malignancy.T ying proteomic to spectral information and machine learning advances our understanding of the infrared spectra of liquid biopsies, af ramework that could be applied to probing of any disease.

Infrared spectroscopy of liquid biopsies is a timeand cost-effective approach that may advance biomedical diagnostics. However, the molecular nature of disease-related changes of infrared molecular fingerprints (IMFs) remains poorly understood, impeding the methods applicability. Here we probe 148 human blood sera and reveal the origin of the variations in their IMFs. To that end, we supplemented infrared spectroscopy with biochemical fractionation and proteomic profiling, providing molecular information about serum composition. Using lung cancer as an example of a medical condition, we demonstrate that the disease-related differences in IMFs are dominated by contributions from twelve highly abundant proteins-that, if used as a pattern, may be instrumental for detecting malignancy. Tying proteomic to spectral information and machine learning advances our understanding of the infrared spectra of liquid biopsies, a framework that could be applied to probing of any disease.

Aquatic photosynthetic organisms evolved to use a variety of light frequencies to perform photosynthesis. Phycobiliprotein phycocyanin 645 (PC645) is a light-harvesting complex in cryptophyte algae able to transfer the absorbed green solar light to other antennas with over 99% efficiency. The infrared signatures of the phycobilin pigments embedded in PC645 are difficult to access and could provide useful information to understand the mechanism behind the high efficiency of energy transfer in PC645. We use visible-pump IR-probe and two-dimensional electronic vibrational spectroscopy to study the dynamical evolution and assign the fingerprint mid-infrared signatures to each pigment in PC645. Here, we report the pigment-specific vibrational markers that enable us to track the spatial flow of excitation energy between the phycobilin pigment pairs. We speculate that two high-frequency modes (1588 and 1596 cm–1) are involved in the vibronic coupling leading to fast (

As napshot of blood serum composition … …r eflects the health state of an individual. It can be obtained using infrared spectroscopy in as imple and inexpensive manner,b ut the molecular nature of the disease-related changes therein remains poorly understood. In their Research Article on page 17060, Liudmila Voronina, Mihaela Ž igman et al. used proteomics to reveal aset of proteins that contribute the most to infrared absorption of blood serum and show that they create adistinct signature of lung cancer.

Eine Momentaufnahme … …d er Zusammensetzung des Blutserums spiegelt den Gesundheitszustand eines Individuums wider. Eine solche Analyse kann mithilfe der Infrarotspektroskopie auf einfache Weise erstellt werden, allerdings bleibt die molekulare Natur der krankheitsbedingten Veränderungen schlecht verstanden. In ihrem Forschungsartikel auf S. 17197 identifizieren Liudmila Voronina, Mihaela Ž igman et al. mittels Proteomik eine Reihe von Proteinen, die am stärksten zur Infrarot-Absorption des Blutserums beitragen und zeigen, dass sie eine eindeutige Signatur von Lungenkrebs erzeugen.

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Spectral congestion challenges spectroscopic studies of the Photosystem II (PSII) light harvesting antenna dynamics. The higher resolution of two-dimensional electronic-vibrational spectroscopy provides new insights into the PSII supercomplex dynamics.