• The excited singlet, triplet, and ionic states are identified, and intersystem crossing, isomerization, electron transfer and recombination, and photothermal conversion due to excited-state annihilation are analyzed, just as by transmittance mode spectroscopy. (iupac.org)
  • Articles, abstracts, and book chapters citing Globals Software (Globals Unlimited, Globals for Spectroscopy, and Globals for Images aka SimFCS) by authors not affiliated with the Laboratory for Fluorescence Dynamics (LFD). (uci.edu)
  • The photo-transformation of HDOM was analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), multiple spectroscopy methods, high-performance liquid chromatography, and combining synchronous fluorescence and Fourier-transform infrared spectroscopy with two-dimensional correlation spectroscopy. (bvsalud.org)
  • Near-infrared Excited Raman Spectroscopy and Its Biomedical Applications. (hamalab.com)
  • This has severely limited the ability to observe biological processes with more than five interacting components," said Behrouz Shabestari, Ph.D., director of the NIBIB program in Optical Imaging and Spectroscopy, "making it impossible to observe complex systems such as molecular pathways that result in tumor formation or patterns of neuronal activation in the brain. (sciencedaily.com)
  • Similar SMLM techniques include Photoactivated Localization Microscopy ( PALM) and Ground State Depletion Individual Molecule Return ( GSDIM) , among many others. (microscopyu.com)
  • It most commonly occurs in fluorescence microscopy, where the over excitation of the material or overexposure causes the fluorophore to permanently lose its ability to fluoresce due to the photon-induced chemical damage and covalent modification 2 . (vassar.edu)
  • The once weakness of the fluorescent microscopy process is now seen as a strength that allows for increased identification of cellular targets. (vassar.edu)
  • This class of dyes finds widespread use as sensors and probes in bio-related research, among them fluorescence confocal microscopy imaging. (uhu.es)
  • The lasers commonly employed in optical microscopy are high-intensity monochromatic light sources, which are useful as tools for a variety of techniques including optical trapping, lifetime imaging studies, photobleaching recovery, and total internal reflection fluorescence. (fsu.edu)
  • In addition, lasers are also the most common light source for scanning confocal fluorescence microscopy, and have been utilized, although less frequently, in conventional widefield fluorescence investigations. (fsu.edu)
  • Illustrated in Figure 1 is a self mode-locked Ti:sapphire pulsed laser, which is currently one of the preferred laser excitation sources in a majority of multiphoton fluorescence microscopy investigations. (fsu.edu)
  • For the first time, pyranine (8-hydroxypyrene-1,3,6-trisulfonate, HPTS) is studied for realizing active plasmonic control, which is attracted considerable attention owing to its unique photophysical and photochemical properties. (ac.ir)
  • Among these, the ESPT performing dynamic role in determining the photophysical and photo-chemical properties of organic molecules, which usually shows dual fluorescence behaviour [17,18]. (researchsquare.com)
  • Dynamic reflection spectroscopies of total internal, diffuse, and regular reflection modes analyze photophysical and photochemical processes at the interface/surface layers with thicknesses of a few tens to a few hundreds of nm and of optically scattering materials. (iupac.org)
  • Based on the detailed photochemical and photophysical characterization a molecular keypad lock and a D-latch memory device were developed and demonstrated. (uhu.es)
  • Crespo-Hernández, C. E. "Photochemical Stability of 5-Methylcytidine Relative to Cytidine: Photophysical Insight for mRNA Therapeutic Applications", ChemRxiv 2023, DOI: https://doi.org/10.26434/chemrxiv-2023-v0q44. (case.edu)
  • This absorption creates excitation energy (change from a ground electronic state to an excited state of the collecting chlorophyll ), which is transferred from one chlorophyll to the next to the photosynthetic reaction centre where it is converted into chemical potential energy (by charge separation). (cea.fr)
  • For nanosecond and femtosecond ablation, we propose cyclic multiphotonic absorption and photomechanical mechanisms, respectively, while purely photochemical ablation was confirmed. (iupac.org)
  • Chan, M. S. and J. R. Bolton (1980) Structures, reduction potentials and absorption maxima of synthetic dyes of interest in photochemical solar-energy storage studies. (photochemcad.com)
  • Original research projects in the field of the dynamics of photoinduced charge separation will make use in particular of ultrafast laser transient absorption and broadband fluorescence upconversion spectroscopies. (epfl.ch)
  • This is a chemical reaction initiated by the absorption of energy in the form of light, with the consequence of the creation of transient excited states with differing chemical and physical properties 1 . (vassar.edu)
  • Dietzek, B., W. Kiefer, G. Hermann, J. Popp and M. Schmitt (2006) Solvent effects on the excited-state processes of protochlorophyllide: a femtosecond time-resolved absorption study. (photochemcad.com)
  • The main way to improve photosynthetic efficiency is to optimize the light reactions, including increasing light absorption and conversion, accelerating the recovery of non-photochemical quenching, modifying enzymes in the Calvin cycle, introducing carbon concentration mechanisms into C 3 plants, rebuilding the photorespiration pathway, de novo synthesis, and changing stomatal conductance. (encyclopedia.pub)
  • The excited states created by UV absorption are endowed with mechanisms of deactivation which are of major importance for the photochemical stability of these species. (cea.fr)
  • For maximum PTT/PDT synergistic efficacy, the concentration of photosensitizers and nanogold required optimization, besides the wavelength of the light matching the absorption peak of PS and nanogold, and the sequential order of PTT and PDT process. (crimsonpublishers.com)
  • Optical absorption and fluorescence spectra of HB sheets indicate that their bandgap energy is 2.8 eV. (nature.com)
  • According to first-principles calculations, optical absorption seen at 2.8 eV is assigned to the electron transition between the σ-bonding states of B and H orbitals. (nature.com)
  • Based on the experimental results, researchers have proposed several categories of signalling mechanisms for fluoride chemosensor, such as photo-induced electron transfer (PET), intramolecular charge transfer (ICT), excimer and exciplex formation, metal ligand charge transfer (MLCT), excited-state intramolecular proton transfer etc. [13-16]. (researchsquare.com)
  • B) The use of photochemical reagents to carry out site-specific reactions on DNA, in particular those involving photo-induced electron transfer. (tcd.ie)
  • In addition, penetration, electron transfer and fluorescence models have been studied. (kau.se)
  • The multiple imaging modes afforded by widefield, confocal, and multiphoton fluorescence microscopies permit noninvasive, temporally resolved imaging of fixed and living cells and tissues with a high level of biochemical specificity. (microscopyu.com)
  • As with all imaging techniques STORM is not without certain critical steps, specifically the user is forced to follow much more stringent sample preparation protocols than dictated by more conventional techniques, such as confocal or widefield fluorescence. (microscopyu.com)
  • Excited chlorophyll dissipates the absorbed light energy by driving photosynthesis (photochemical energy conversion), as heat in non-photochemical quenching or by emission as fluorescence radiation. (wikipedia.org)
  • To use measurements of chlorophyll fluorescence to analyse photosynthesis, researchers must distinguish between photochemical quenching and non-photochemical quenching (heat dissipation). (wikipedia.org)
  • To make this process truly sustainable, researchers are trying to run it on sunlight in the same way plants do during photosynthesis. (chemistryworld.com)
  • Photosynthesis is the largest mass- and energy-conversion process on Earth, and it is the material basis for almost all biological activities. (encyclopedia.pub)
  • Photosynthesis refers to the process in which autotrophs convert light energy from the sun into chemical energy to convert inorganic carbon into complex organic carbon and release oxygen. (encyclopedia.pub)
  • The process of photosynthesis can be basically divided into two stages: light and dark reactions. (encyclopedia.pub)
  • The light reactions of photosynthesis are the starting points of the whole photosynthesis process, providing adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) as the energy sources for the subsequent dark reactions, and part of the ATP and NADPH generated enters the photorespiratory pathway. (encyclopedia.pub)
  • Carbon assimilation is the carbon-reaction stage of photosynthesis, which is essentially a process of inorganic carbon fixation and conversion to organic carbon. (encyclopedia.pub)
  • The increase in fluorescence is due to PSII reaction centers being in a "closed" or chemically reduced state. (wikipedia.org)
  • Closed reaction centres reduce the overall photochemical efficiency, and so increases the level of fluorescence. (wikipedia.org)
  • Transferring a leaf from dark into light increases the proportion of closed PSII reaction centres, so fluorescence levels increase for 1-2 seconds. (wikipedia.org)
  • Fluorescence level of dark-adapted sample when all reaction centers of the photosystem II are open. (wikipedia.org)
  • The presence of the bicontinuous structures formed by the upconverting fibrous nanoassemblies and the solution phase is utilized to design photochemical reaction systems induced by TTA-UC. (mdpi.com)
  • 9 In 1924, Vavilov referred to the term "fluorescence yield", based on Warburg's earlier work, to calculate the fraction of absorbed rays of light to fluorescent rays of light, 10 whereas the term "molecules per quantum light absorbed" appears in a paper published in 1925 by Marshall to describe the photochemical reaction between hydrogen and chlorine. (edinst.com)
  • Chlorophyll fluorescence is light re-emitted by chlorophyll molecules during return from excited to non-excited states. (wikipedia.org)
  • Berlman, I. B. (1971) Handbook of Fluorescence Spectra of Aromatic Molecules. (photochemcad.com)
  • The principles of the reactivity of excited states of molecules and solids under irradiation are detailed. (epfl.ch)
  • Photobleaching is the photochemical alteration of a dye or fluorophore molecules that removes its ability to fluoresce. (vassar.edu)
  • Most students are introduced to photobleaching in introductory Biology courses, where the process is exploited to study the diffusion properties of cellular components in molecules by observing the recovery or loss of fluorescence to a photobleached site. (vassar.edu)
  • The process in which pigment molecules produce electrons by capturing solar energy is called photosynthetic electron transport (PET). (encyclopedia.pub)
  • The group used the system to examine normal and diseased brain tissue and found that there were different patterns of distribution of certain molecules in the diseased versus normal state. (sciencedaily.com)
  • As these processes are complementary processes, the analysis of chlorophyll fluorescence is an important tool in plant research with a wide spectrum of applications. (wikipedia.org)
  • This variable rise in chlorophyll fluorescence rise is due to photosystem II. (wikipedia.org)
  • Heat dissipation cannot be totally stopped, so the yield of chlorophyll fluorescence in the absence of non-photochemical quenching cannot be measured. (wikipedia.org)
  • This last mechanism, which is multifactorial, is known as the non-photochemical quenching of chlorophyll fluorescence . (cea.fr)
  • Excited chlorophyll pigments transfer their energy to carotenoid pigments, which immediately dissipate it as heat. (cea.fr)
  • Their study, published in JBC, shows that, in this state, all the changes associated with non-photochemical quenching (changes in protein-chlorophyll interactions, neoxanthin torsion) are present except for lutein torsion , while no quenching is associated with this state . (cea.fr)
  • Drzewiecka-Matuszek, A., A. Skalna, A. Karocki, G. Stochel and L. Fiedor (2005) Effects of heavy central metal on the ground and excited states of chlorophyll. (photochemcad.com)
  • Fluorescence and Rayleigh light-scattering spectroscopies are developed for elucidating excited-state dynamics of single nanoparticles. (iupac.org)
  • Crespo-Hernández, C. E. "Excited State Dynamics of Dibenzothiophene Derivatives", J. Phys. (case.edu)
  • Crespo-Hernández, C. E. "Excited State Dynamics of Dibenzothiophene Derivatives", ChemRxiv 2023, https://doi.org/10.26434/chemrxiv-2023-kwwr2. (case.edu)
  • Crespo-Hernández, C. E., "Excited State Dynamics of 2'-Deoxyisoguanosine and Isoguanosine in Aqueous Solutions", Phys. (case.edu)
  • submitted as part of the Special Issue "Ultrafast Dynamics in Chemical Processes" . (case.edu)
  • Chen, R. F. and C. H. Scott (1985) Atlas of fluorescence spectra and lifetimes of dyes attached to protein. (photochemcad.com)
  • Neutral-network approach to qualitative identification of fuels and oils from laser-induced fluorescence-spectra. (cdc.gov)
  • Following blue or red light activation, porphyrins are excited to a higher energy triplet state, which can either emit light (fluorescence) or generate reactive oxygen species, such as singlet oxygen or free radicals. (medscape.com)
  • The generation of singlet oxygen species, labeled type 2 photochemical reactions, are believed to predominate in photodynamic therapy. (medscape.com)
  • Furthermore, the photo-transformation of HDOMs was accompanied by the generation of triple excited state dissolved organic matter and singlet oxygen. (bvsalud.org)
  • The dramatic history of mechanistic studies of oxygen photoactivation is reviewed starting from the Bach-Engler peroxidation theory to the hypothesis of moloxide, discovery of singlet oxygen and free radicals and, then, to modern views on the primary photoactivation processes. (msu.ru)
  • Studying the movement of electrons via transitions from the singlet state to the triplet state gives us a better conceptual grasp on the photobleaching process with a molecular focus on energy levels and the wavefunctions of the different spin states. (vassar.edu)
  • The origin of widely used division of photodynamic processes into type I and type II and the relation of these processes to the nature of the primary photochemical reactions of photosensitizers are discussed. (msu.ru)
  • b) Strong laser excitation pushes most fluorophores to a dark state, from which single fluorophores may stochastically return to an emissive state (highlighted in yellow), the centroid position identified (illustrated by black crosses), and finally mapped in a single composite super-resolution reconstruction (f). (microscopyu.com)
  • The observed changes are due to the change of states from electron excitation via intersystem crossing. (vassar.edu)
  • Corral, I. "Disclosing the role of C4-oxo substitution in the photochemistry of DNA and RNA pyrimidine monomers: Formation of photoproducts from the vibrationally-excited ground state", ChemRxiv 2022, https://doi.org/10.26434/chemrxiv-2022-qmnkv. (case.edu)
  • Aggregates of cationic calix[4]arenes in aqueous solution as media for governing protolytic equilibrium, fluorescence, and kinetics (2022) Journal of Molecular Liquids, 366, статья № 119940, Цитировано 2 раз. (org.ua)
  • 1.6 What do standard heats of formation tell us about chemical bonding and ground-state properties of organic compounds? (dattanibookagency.in)
  • The binding of dissolved organic matter (DOM) with metals affects the latter's biogeochemical processing in the environment. (bvsalud.org)
  • Recently, in situ YSI EXO2 phycocyanin fluorescence probes have been widely deployed as a means to determine cyanobacterial abundance in drinking water sources, yet few studies have evaluated the effects of natural organic matter (NOM) and the ambient water temperature on the probe readings. (mdpi.com)
  • Hot excited state management for long-lived blue phosphorescent organic light-emitting diodes. (nature.com)
  • Recently, our group established the synthesis of the hydrogen boride nanosheets (HB sheets) with a well-defined chemical composition using a facile ion-exchange technique in an organic solvent through an exfoliation process 15 . (nature.com)
  • Luciferases have become indispensable for the study of fundamental cellular processes including the regulation of transcription and translation, mRNA and protein stability, and nucleic acid/protein interactions. (neb.com)
  • This property can be exploited in applications requiring a polarized illumination source, such as differential interference contrast, polarized light measurements, or quantitative investigations of fluorescence polarization anisotropy. (fsu.edu)
  • Such an approach has been developed by a collaboration between the SBM team of LFP (CEA-CNRS URA2453), a theoretical team of the Ruđer Bošković Institut (Zagreb, Croatia) and two experimentalists of CLUPS (Paris Sud University, Orsay) in order to characterize the excited states of the stable conformers of a model peptide and establish the nonradiative relaxation mechanisms. (cea.fr)
  • By switching the UV light on and off, the HPTS thin film maintains an excited-state proton transfer (ESPT) process followed by green fluorescence resulting in a plasmonic redshift caused by the variation of the refractive index. (ac.ir)
  • The results indicate that the excited-state proton transfer (ESPT) process from N-H group nearby the anthracene moiety. (researchsquare.com)
  • I will further explore what it means for electrons to change state and which kind of transitions are more probable than others by studying the selection rules and the principles that support their claims. (vassar.edu)
  • With these electrons, it generates a super reductant state that drives the carbon dioxide reduction. (chemistryworld.com)
  • The majority of these processes are ultrafast and provide a rapid and efficient way to dissipate the electronic energy into vibration, thus avoiding photochemical reactions. (cea.fr)
  • In a study published in JBC, a team from I2BC/CEA-Joliot, in collaboration with the Beijing Botanical Institute (China), describes for the first time an intermediate state of the light-harvesting antenna of higher plants that provides a better understanding of the changes that take place at the molecular level during the activation of a plant's photoprotection mechanism. (cea.fr)
  • In view of the fact that ions play a major role in many chemical and biological process, designing ion selective molecular sensors is a challenging entity in supramolecular chemistry [1,2]. (researchsquare.com)
  • There are many experimental reports as molecular optical sensors, while very few reports of selective fluorescence fluoride sensor is seen, due to the surface charge density and similar basicity of fluoride ion with other ions [9-12]. (researchsquare.com)
  • This doctoral thesis contributes to these activities with the design and characterization of new molecular switches and model systems that can be used to study energy transfer processes. (uhu.es)
  • As an additional advantage the logic functions can be reset and reconfigured, which makes the system a versatile platform for molecular information processing. (uhu.es)
  • Photochromic molecular switches (fluorophore-appended spiropyrans and a fulgimide) that can deliver distinct fluorescence responses depending on their ring-open and ring-closed states were investigated. (uhu.es)
  • Such switches are not trivial and the developed research is without doubt at the frontline of these recent developments in molecular information processing. (uhu.es)
  • A conception stating that molecular oxygen is chemically rather passive and special activation mechanisms are needed to involve it into chemical and biological processes appeared in the scientific literature in the middle of XIX century. (msu.ru)
  • Connolly, J. S., E. B. Samuel and A. F. Janzen (1982) Effects of solvent on the fluorescence properties of bacteriochlorophyll α. (photochemcad.com)
  • This state of LHCII should be considered as a n intermediate state that would allow the transition from an unquenched state, capable of absorbing and converting light energy into chemical energy, to a 'quenched' state through non-photochemical quenching . (cea.fr)
  • The transition state (TS) calculations were performed to understand the thermodynamic features and mechanism of host-guest interaction. (researchsquare.com)
  • Transitions are only detectable when the transition moment dipole is nonzero and when the wavefunctions include the initial and final states which contain both the electronic and nuclear wave functions (2). (vassar.edu)
  • Fermi's Golden Rule (4), which describes the transition rate or probability of transition per unit time from one eigenstate to another and is only allowed if the initial and final states have the same energy, allows M, the electric dipole moment operator to replace the time dependent Hamiltonian (5), giving that final transition moment integral that describes electronic transitions from ground to excited states (6). (vassar.edu)
  • Since the integral must be non-zero for the transition to occur, the two states must overlap, as per the Franck-Cordon principle which states that the probability of electric transition is more likely if the wavefunctions overlap. (vassar.edu)
  • Transition metal complexes have diverse metal d electron configurations, oxidation states, coordination numbers and geometries such that they can undergo a diverse array of electronic transitions. (nature.com)
  • In addition, density functional theory (DFT) calculations suggest the other allowed transition from the σ-bonding state of B and H orbitals to the antibonding state with the gap of 3.8 eV. (nature.com)
  • Significant gaseous H 2 release is found to occur only under photoirradiation, which causes the electron transition from the σ-bonding state to the antibonding state even under mild ambient conditions. (nature.com)
  • Figure 1 Quantum yield and radiative and non-radiative decay processes. (edinst.com)
  • Cet enseignement vise l'établissement de bases solides en chimie quantitative. (epfl.ch)
  • Metal-to-ligand charge-transfer transitions and their associated excited states are especially attractive given their rich redox properties and robustness. (nature.com)
  • The impact of temperature on phycocyanin fluorescence was evaluated by monitoring the laboratory cultivated cyanobacterial species and extracted phycocyanin pigment. (mdpi.com)
  • Photodynamic therapy (PDT) involves the use of photochemical reactions mediated through the interaction of photosensitizing agents, light, and oxygen for the treatment of malignant or benign diseases. (medscape.com)
  • Dixon, J. M., M. Taniguchi and J. S. Lindsey (2005) PhotochemCAD 2: a refined program with accompanying spectral database for photochemical calculations. (photochemcad.com)
  • 2. Substitution effect on spectral and acid-base properties in the ground and excited states, The Journal of Physical Chemistry. (edu.pl)
  • Yu, A.* Interaction between triethanolamine and singlet or triplet excited state of xanthene dyes in aqueous solution. (ruc.edu.cn)
  • However, due to some inherent limitations of current Fd-OCT technology (e.g., lack of spectroscopic information, inability to measure fluorescent signals), it is important to co-register Fd-OCT data with images obtained by other clinical imaging modalities such as fundus cameras and fluorescence angiography to create a more complete interpretation and representation of structures imaged. (spie.org)
  • Nocera, D. G. Chemistry of the multielectron excited state. (nature.com)
  • Furthermore, this photochemical active medium has also played another important role in plasmonic sensing, in which the emission-based response of HPTS thin film in 2D-plasmonic grating to water vapor upon photoexcitation is demonstrated, for both s and p polarizations. (ac.ir)
  • Fluoride ion is a necessary trace element in the human body, which has vital role in a broad range of chemical, biological and environmental processes [3-5]. (researchsquare.com)
  • Seeing is believing," has been taken to heart by researchers as they strive to develop microscopes that will reveal biological structures and processes with increased clarity and detail. (sciencedaily.com)
  • 6 The quantum yield is therefore the probability that a system in the excited state deactivates through a radiative process to its ground state. (edinst.com)
  • I wonder if they could also produce enzymes that could do very difficult reactions, such as nitrogen reduction - that would be really exciting. (chemistryworld.com)
  • Single-photon source for quantum information based on single dye molecule fluorescence in liquid crystal host Lukishova SG, Knox RP, Freivald P, et al. (rochester.edu)
  • In the ground state of receptor-fluoride complex, the added fluoride ion made hydrogen bond through N−H … F … H−N. Whereas, the intramolecular hydrogen bonding was through F−H … N in the excited state of receptor-fluoride complex. (researchsquare.com)
  • The natural bond orbital analyses show the second perturbation energy for donor-acceptor interaction of F - with hydrogen is more than 300 kcal/mol at the excited state of receptor-fluoride complex, which indicates the strong single bond between fluoride and hydrogen atom. (researchsquare.com)
  • The efficiency of non-photochemical quenching is altered by various internal and external factors. (wikipedia.org)
  • STORM and other SMLMs are conceptually similar techniques: the photochemical properties of the fluorophore are exploited to induce a weakly emissive or non-emissive "dark" state. (microscopyu.com)
  • From the dark state, very small populations of (ideally) fluorophore are returned to an emissive state, excited, and detected. (microscopyu.com)
  • Remarkably, the team succeeded in isolating for the first time a state of LHCII, obtained using the detergent n-dodecyl-α-D-maltoside , and in characterising the spectroscopic properties of its pigments . (cea.fr)
  • Despite the advantages of traditional fluorescence microscopies, the spatial resolution of such techniques is limited by the diffraction of light ( diffraction barrier ). (microscopyu.com)
  • Energy Frontier Research Centers (EFRC) (United States). (osti.gov)
  • The results showed that with the increase of carbonization temperature, amide II in protein-like substances were observed to be preferentially photolyzed, and the protein-like substances were more sensitive to low irradiation time, while the duration time of the photochemical behavior of amide II and aliphatic C-H were more persistent. (bvsalud.org)
  • To reduce photochemical quenching to negligible levels, a high intensity, short flash of light is applied to the leaf. (wikipedia.org)
  • Fluorescence level of light-adapted sample when a high intensity pulse has been applied. (wikipedia.org)
  • It catalyzes the oxidative decarboxylation of coelenterazine to produce coelenteramide via an excited state intermediate, which upon relaxation to the ground state emits blue light (475 nm) (Figure 2). (neb.com)
  • Green fluorescence increased ∼1.9 times in high light corals and decreased ∼1.9 times in low light corals compared with medium light corals. (biologists.com)