• Excited state intramolecular proton transfer (ESIPT) is a process in which photoexcited molecules relax their energy through tautomerization by transfer of protons. (wikipedia.org)
  • Some kinds of molecules could have different minimum-energy tautomers in different electronic states, and if the molecular structure of minimum-energy tautomer in the excited state is proton-transferred geometry between neighboring atoms, proton transfer in excited state can occur. (wikipedia.org)
  • The anthracene-localized excitation was observed to transfer across the molecule, to the phenol-pyridine, where a concomitant proton transfer occurred. (avhandlingar.se)
  • The primary steps and the wavepacket dynamics of the ultrafast photoinduced double proton transfer in (2,2'-bipyridyl)-3,3'-diol are observed. (uni-muenchen.de)
  • We find that the first step of the sequential proton transfer and the concerted double proton transfer both proceed in about 50 fs. (uni-muenchen.de)
  • ii) a nonsymmetric in-plane-bending mode is associated with the sequential proton transfer and provides evidence that the transient reduction of the donor acceptor distance occurs only in one chelate ring. (uni-muenchen.de)
  • In biological redox catalysis, energy transduction, and many aspects of regulation, electron transfer (ET) is linked directly to conformational change, ligand/substrate binding, ion/proton transfer etc., and the ways in which these events occur and how the system as a whole is optimised and harmonised are still not well understood. (science24.com)
  • Exploration of the potential energy surface confirmed the identified minimum and provided support for vibrationally induced intramolecular proton transfer within the complex. (elsevierpure.com)
  • These results make the O 2 - - HF complex an excellent prototype for infrared spectroscopic investigations on open-shell complexes with vibrationally induced proton transfer. (elsevierpure.com)
  • The reorganization energy accompanying intramolecular electron-transfer within this system (λ ≈ 0.86 eV) has been determined by fitting the rates of photoinduced and thermal reactions to a single-mode quantum-mechanical ET model. (caltech.edu)
  • Using the emerging technique of ultrafast two-dimensional infrared spectroscopy, we show that, similarly to other transition-metal complexes, the central Ru heavy atom acts as a "bottleneck" making the energy transfer from small ligands with high energy vibrational stretching frequencies less favorable and thereby affecting the efficiency of vibrational energy flow in the complex. (rsc.org)
  • We find that the ultrafast intramolecular relaxation is strongly coupled to a specific vibrational mode, resulting in the concerted transfer of population and coherence between excited states on a sub-100 fs timescale. (lu.se)
  • Next, water-soluble biliverdin is reduced to bilirubin, which, because of the intramolecular hydrogen bonds, is almost insoluble in water in its most common isomeric form (bilirubin IXα Z,Z). Because of its hydrophobic nature, unconjugated bilirubin is transported in the plasma tightly bound to albumin. (medscape.com)
  • Rate of ESIPT process may slow down by deuterium substitution of hydrogen that is transferred in ESIPT, because the deuteration increases only mass of the transferred significantly while do not change electrostatic potential in the molecule substantially. (wikipedia.org)
  • We propose to explain this observation by the intramolecular electrostatic interactions between the thiocyanate group and partially oxidised Ru metal center, which increase the degree of vibrational coupling between CN and Ru-N modes in the excited state thus reducing structural and thermodynamic barriers that slow down vibrational relaxation and energy transport in the electronic ground state. (rsc.org)
  • Therewith, a successful simulation of the molecular surfaces of enzyme biological partners, e.g. cytochrome c, by the SAM of alkanethiols on gold may provide the necessary amount/orientation of the enzyme molecules for direct ET reaction with the electrode, as well as a conformation appropriate for efficient intramolecular ET, including electrostatic compatibility of the docking sites and the aspect of mobility in achieving a proper orientation for fast ET. (science24.com)
  • Here we report on a multidimensional spectroscopy investigation of the energy-level structure and the early-time relaxation cascade, which eventually results in the population of an emitting state. (lu.se)
  • Neutron Spin-Echo spectroscopy (NSE) on the other hand, offers the highest energy resolution in the field of neutron spectroscopy and allows the study of slow collective motions in proteins up to several hundred nanoseconds and in the nanometer length-scale. (lu.se)
  • Careful consideration of the redox properties of the donor relative to the acceptor units allows for avoidance of potentially deleterious excited-state electron-transfer processes. (rsc.org)
  • Moreover, if the charge did initially localize, would it, at some point in time, transfer in between the ligands, hence perform interligand electron transfer? (avhandlingar.se)
  • The results confirm the existence of an initial localization onto one ligand, and that interligand electron transfer occurs on a sub-picosecond time scale. (avhandlingar.se)
  • In photocatalysis, a concerted proton and electron transfer is sought after, as the total charge neutralizes thus avoids the formation of high energy intermediates. (avhandlingar.se)
  • To further improve the ortho-linkage concept, the impact of incorporating planarized electron-donating triarylamine (TAA) structures on intramolecular charge transfer was examined. (unige.ch)
  • Applications to photochemical reactivity are focused on problems involving at least two potential surfaces, known as non-adiabatic chemistry, including photochemistry and electron transfer. (imperial.ac.uk)
  • An ionisation energy of 5.5 eV and an electron affinity of 3.3 eV were estimated by cyclic voltammetry measurements. (beilstein-journals.org)
  • The catalytic activity of NiR is measured electrochemically by exploiting a direct electron transfer to fluorescently labeled enzyme molecules immobilized on modified gold electrodes, whereas the redox state of the type-1 copper site is determined from fluorescence intensity changes caused by Förster Resonance Energy Transfer (FRET) between a fluorophore attached to NiR and its type-1 copper site. (science24.com)
  • The homotrimeric structure of the enzyme is reflected in heterogeneous interfacial electron transfer kinetics with two monomers having a 25-fold slower kinetics than the third monomer. (science24.com)
  • The intramolecular electron transfer rate between the type-1 and type-2 copper site changes at high nitrite concentration (≥520 mM) resulting in an inhibition effect at low pH and catalytic gain in enzyme activity at high pH. (science24.com)
  • This effect is attributed to slower reduction rate of type-2 copper centre due to a rate-limiting protonation step of residues in the enzyme's active site, gating the intramolecular electron transfer. (science24.com)
  • A picosecond transient absorption experiment has been constructed and used for the study of intramolecular electron-transfer (ET) in three molecular systems. (caltech.edu)
  • Less comprehensive studies of two other electron-transfer systems are also reported. (caltech.edu)
  • Studies of biological electron transfer (ET) within multi-cofactor redox enzymes under conditions when the electrode replaces the natural redox partner of the enzyme can contribute to understanding intramolecular ET within the biomolecules followed by ET coupling of the active sites. (science24.com)
  • Heat transfer to both perovskite compositions of comparable sizes is similar (25-30 ps), due to fast intramolecular vibrational relaxation and similar matching of low-energy phonons with the organic ligand, but FAPbBr 3 samples show a slow bleaching kinetic on the order of 1 ns. (osti.gov)
  • This work examines the transfer of thermal excitation from an organic ligand coating to either all-inorganic cesium lead tribromide (CsPbBr 3 ) nanocrystals or hybrid organic-inorganic formamidinium lead tribromide (FAPbBr 3 ) nano crystals using selective infrared optical excitation. (osti.gov)
  • tpy = 2,2',2"-terpyridine), our transient absorption experiment is able to detect formation of a charge-separated state following excitation into the Ru → immine charge-transfer band. (caltech.edu)
  • The investigation provides novel insight into the dynamics of an intramolecular excitation energy transfer mechanism that can be used to activate long-lived metal centered excited states of importance for emerging photocatalytic and sustainable solar energy conversion applications. (lu.se)
  • Schulze, T. F. & Schmidt, T. W. Photochemical upconversion: present status and prospects for its application to solar energy conversion. (nature.com)
  • Since a proton-transferred geometry is usually the minimum-energy tautomer only in the excited state and relatively unstable in the ground state, molecules that have ESIPT character may show extraordinarily larger Stokes shift than common fluorescent molecules, or exhibit dual fluorescence that shorter-wavelength one comes from the original tautomer and longer-wavelength one from proton-transferred tautomer. (wikipedia.org)
  • However, there are some exceptional cases where ESIPT molecules have no dual luminescence or significantly red-shifted emission from proton-transferred tautomer, from various reasons. (wikipedia.org)
  • The triplet-state violanthrone chromophores luminesce in the visible spectrum following energy delivery from two singlet oxygen molecules. (nature.com)
  • The results show that this series of molecules is well suited for a mechanistic study of short-range intramolecular electronic energy transfer. (haifa.ac.il)
  • Both temperature and isotope effects suggest that the molecules' low internal reorganization energies (λ in = 0.006 eV) account for their ET behavior. (caltech.edu)
  • The intramolecular energy transfer process is investigated and quantified in terms of the quantum yield of the energy transfer and is found to be highly effective in these molecules. (edu.hk)
  • Understanding the dynamics of the initial stages of vibrational energy transfer in transition metal complexes is a challenging fundamental question which is also of crucial importance for many applications, such as improving the performance of solar devices or photocatalysis. (rsc.org)
  • As a very similar behavior was earlier observed in another transition-metal complex, Re(4,4′-(COOEt) 2 -2,2′-bpy)(CO) 3 Cl, we suggest that this effect in vibrational energy dynamics might be common for transition-metal complexes with heavy central atoms. (rsc.org)
  • The critical transfer radius for electronic energy transfer from the aromatic (donor) chromophore to the α-diketone (acceptor) chromophore was calculated from the spectral overlap between the fluorescence spectrum of the aromatic moiety and the absorption spectrum of the α-diketone moiety. (haifa.ac.il)
  • It is proposed that the results correlate with an increasing ortho-linkage effect and decreasing donor strength of the TAA moiety by planarization and, thus, tackling one of the major challenges in PHOLED research: improving both triplet energy and compound stability. (unige.ch)
  • Ab initio molecular dynamics simulations support the hypothesis that low-energy inorganic sublattice phonon modes are populated initially in the heat transfer process, with a slow thermal population of the higher-energy phonon modes associated primarily with the organic cation. (osti.gov)
  • Intramolecular Energy and Solvent-Dependent Chirality Transfer within a BINOL-Perylene Hetero-Cyclophane. (bvsalud.org)
  • Energy transfer in the present system can be described as occurring via a through-space energy-transfer mechanism. (rsc.org)
  • By incorporating organic chromophores as ligands onto the PbS nanocrystals to improve energy transfer, we demonstrate that violanthrone upconverts in the absence of oxygen by the triplet-triplet annihilation mechanism. (nature.com)
  • Fig. 1: A cartoon showing the energy flow and mechanism of nanocrystal-sensitized PUC. (nature.com)
  • This proton-coupled energy transfer mechanism, is a new phenomenon that further adds to the knowledge of charge transfer mechanisms. (avhandlingar.se)
  • The reversible system converts energy of the proton translocation to the synthesis or hydrolysis of ATP (30 kJ/mole ATP at pH7). (mpsd.de)
  • The enzyme couples the vectorial proton transport accross a membrane with the synthesis or cleavage of the energy rich compound ATP (AdenosineTriPhosphate) in a reversible reaction. (mpsd.de)
  • However the amount of rate change may lie in the range of 1~50, depending on the shape and size of potential energy surfaces of the molecule. (wikipedia.org)
  • The focus of this thesis has been to study how electrons and protons transfer between different fragments of a molecule, following an absorption of laser light. (avhandlingar.se)
  • The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. (hud.ac.uk)
  • Fawzy, WM , Elsayed, M & Zhang, Y 2013, ' Correlated ab initio investigations on the intermolecular and intramolecular potential energy surfaces in the ground electronic state of the O 2 - (X 2 Π g )- HF (X 1 Σ + ) complex ', Journal of Chemical Physics , vol. 138, no. 1, 014304. (elsevierpure.com)
  • We have used oligonucleotides containing molecular beacons to determine melting profiles for intramolecular DNA duplexes, triplexes and quadruplexes (tetraplexes). (soton.ac.uk)
  • The intramolecular energy transfer is maintained by a series of molecular motions. (mpsd.de)
  • 2. Thermal stability - monoglyceride results from intramolecular acyl transfers. (iberocruceros.com)
  • The relevance of this work is not only attributed to its mechanistic insights, but also that it might provide a foundation for future designs of renewable energy systems, such as solar cells and fuel cells. (avhandlingar.se)
  • The present study investigates vibrational energy transport in the ground and the electronic excited state of Ru(4,4′-(COOEt) 2 -2,2-bpy) 2 (NCS) 2 , a close relative of the efficient "N3" dye used in dye-sensitized solar cells. (rsc.org)
  • A higher degree of planarization also results in significantly increased singlet and triplet energy values, revealing the impact on the intramolecular charge transfer. (unige.ch)
  • 6 ] By achieving this, the effect of potency on the dye intramolecular charge transfer process[ 7 ] can be examined in detail and any extraneous complicating processes removed. (thieme-connect.com)
  • The NBO analysis, to study the intramolecular hyperconjugative interactions, was carried out. (hud.ac.uk)
  • We propose that the intramolecular rate is significantly reduced in turn-over conditions compared to the enzyme at rest, with an exception at low pH / nitrite conditions. (science24.com)
  • On the basis of potential energy distribution together with the normal-co-ordinate analysis and following the scaled quantum mechanical force methodology, the assignments for the various frequencies were described. (hud.ac.uk)
  • Here, we demonstrate an upconversion composition using PbS semiconductor nanocrystal sensitizers that absorb photons below the bandgap of silicon and populate violanthrone triplet states below the singlet oxygen energy. (nature.com)
  • A half-bridge GaN converter with 99.1 investigated with respect to power conversion efficiency and data transfer. (researchgate.net)
  • Measurements show that, compared to digital PWM, a wider range of current ripple modulation is available for data transfer before the power efficiency drops. (researchgate.net)
  • Progress in developing small energy gap non-fullerene acceptors (NFAs) provides new opportunities to achieve both high efficiency and transparency. (justia.com)
  • The standard HIRO accepts up to 20 W and 1 mJ pump, the high‑power model (HIRO‑HP) takes up to 80 W, and the high‑energy model (HIRO-HE) goes up to 80 W and 4 mJ pump while maintaining the high conversion efficiency and beam quality. (lightcon.com)
  • Results of all levels of calculations predicted two equivalent minimum energy structures of planar geometry and C s symmetry along the A'' surface of the complex, whereas the A' surface is repulsive. (elsevierpure.com)