共查询到20条相似文献,搜索用时 31 毫秒
1.
Adriana García Forero Diego Armando Villamizar Mantilla Luis A. Núez Raquel Elvira Ocazionez Elena E. Stashenko Jorge Luis Fuentes 《Photochemistry and photobiology》2019,95(4):1010-1018
This work evaluated the photoprotective and antigenotoxic effects against ultraviolet B (UVB) radiation of flavonoid compounds apigenin, naringenin and pinocembrin. The photoprotective efficacy of these compounds was estimated using in vitro photoprotection indices, and the antigenotoxicity against UVB radiation was evaluated using the SOS chromotest and an enzymatic (proteinase K/T4 endonuclease V enzyme) comet assay in UV‐treated Escherichia coli and human (HEK‐293) cells, respectively. Naringenin and pinocembrin showed maximum UV‐absorption peak in UVC and UVB zones, while apigenin showed UV‐absorption capability from UVC to UVA range. These compounds acted as UV filters reducing UV‐induced genotoxicity, both in bacteria and in human cells. The enzymatic comet assay resulted highly sensitive for detection of UVB‐induced DNA damage in HEK‐293 cells. In this work, the photoprotective potential of these flavonoids was widely discussed. 相似文献
2.
Photoisomerization of Arylazopyrazole Photoswitches: Stereospecific Excited‐State Relaxation
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Ya‐Ting Wang Dr. Xiang‐Yang Liu Prof. Dr. Ganglong Cui Prof. Dr. Wei‐Hai Fang Prof. Dr. Walter Thiel 《Angewandte Chemie (International ed. in English)》2016,55(45):14009-14013
Electronic structure calculations and nonadiabatic dynamics simulations (more than 2000 trajectories) are used to explore the Z–E photoisomerization mechanism and excited‐state decay dynamics of two arylazopyrazole photoswitches. Two chiral S1/S0 conical intersections with associated enantiomeric S1 relaxation paths that are barrierless and efficient (timescale of ca. 50 fs) were found. For the parent arylazopyrazole (Z8) both paths contribute evenly to the S1 excited‐state decay, whereas for the dimethyl derivative (Z11) each of the two chiral cis minima decays almost exclusively through one specific enantiomeric S1 relaxation path. To our knowledge, the Z11 arylazopyrazole is thus the first example for nearly stereospecific unidirectional excited‐state relaxation. 相似文献
3.
Dr. Julien Briand Dr. Stefania Fusi Dr. Riccardo Rossi Paccani Prof. Massimo Olivucci Prof. Stefan Haacke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(48):15296-15304
The coherent photoisomerization of a chromophore in condensed phase is a rare process in which light energy is funneled into specific molecular vibrations during electronic relaxation from the excited to the ground state. In this work, we employed ultrafast spectroscopy and computational methods to investigate the molecular origin of the coherent motion accompanying the photoisomerization of indanylidene–pyrroline (IP) molecular switches. UV/Vis femtosecond transient absorption gave evidence for an excited‐ and ground‐state vibrational wave packet, which appears as a general feature of the IP compounds investigated. In close resemblance to the coherent photoisomerization of rhodopsin, the sudden onset of a far‐red‐detuned and rapidly blue‐shifting photoproduct signature indicated that the population arriving on the electronic ground state after nonadiabatic decay through the conical intersection (CI) is still very focused in the form of a vibrational wave packet. Semiclassical trajectories were employed to investigate the reaction mechanism. Their analysis showed that coupled double‐bond twisting and ring inversions, already populated during the excited‐state reactive motion, induced periodic changes in π‐conjugation that modulate the ground‐state absorption after the non‐adiabatic decay. This prediction further supports that the observed ground‐state oscillation results from the reactive motion, which is in line with a biomimetic, coherent photoisomerization scenario. The IP compounds thus appear as a model system to investigate the mechanism of mode‐selective photomechanical energy transduction. The presented mechanism opens new perspectives for energy transduction at the molecular level, with applications to the design of efficient molecular devices. 相似文献
4.
Juan C. Mejía‐Giraldo Robert Winkler Cecilia Gallardo Ana M. Sánchez‐Zapata Miguel A. Puertas‐Mejía 《Photochemistry and photobiology》2016,92(5):742-752
In the quest for new natural agents of photoprotection, we evaluated the photoprotective and antioxidant activity of B. antioquensis leaf extracts as well as its phenolic composition. The methanolic extract treated with activated carbon showed the highest absorption coefficients for UVA‐UVB radiation, as well as an antioxidant capacity comparable to butylated hydroxy toluene. Furthermore, the formulation containing this extract showed suitable sensorial and photostable characteristics for topical use, and significant values of UVAPF, critical wavelength (λc), UVA/UVB ratio and sun protection factor (5.3, 378 nm, 0.78 and 9.1 ± 0.1, respectively). In addition, three glycoside derivatives of quercetin, a kaempferol glycoside and a derivative of caffeic acid were the main polyphenolic compounds identified. These results demonstrate the potential of B. antioquensis extracts to be used as active components of novel, natural sunscreens. 相似文献
5.
Relative Contributions of UVB and UVA to the Photoconversion of (6‐4) Photoproducts into their Dewar Valence Isomers
下载免费PDF全文
![点击此处可从《Photochemistry and photobiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Thierry Douki 《Photochemistry and photobiology》2016,92(4):587-594
Dewar valence isomers are photoisomerization products of pyrimidine (6‐4) pyrimidone photoproducts, a major class of UV‐induced DNA lesions, which exhibits a maximal absorption around 320 nm. However, Dewar isomers are not produced in significant amounts in cells exposed to biologically relevant doses of UVB. In contrast, they are readily produced when cells are exposed to a combination of UVA and UVB. The present computational work demonstrates that, on the basis of known absorption properties and formation quantum yields, the difference in Dewar formation between the two types of radiation can be explained by the role of normal bases. In the UVB range, at the low level of (6‐4) photoproducts present in cells exposed to realistic doses, normal bases are present in overwhelming amounts and absorb the vast majority of the incident photons. In contrast, the absorption of DNA bases is much weaker in the UVA range while that of (6‐4) photoproducts is still significant, making photoisomerization possible. This two‐photon process makes it difficult to define an action spectrum for the formation of Dewar isomers. 相似文献
6.
Dr. Tuhin Khan Dr. Radek Litvín Dr. Václav Šebelík Prof. Dr. Tomáš Polívka 《Chemphyschem》2021,22(5):471-480
Carotenoids are molecules with rich photophysics that are in many biological systems involved in photoprotection. Yet, their response to excess energy excitation is only scarcely studied. Here we have explored excited state properties of three keto-carotenoids, echinenone, canthaxanthin and rhodoxanthin after excess energy excitation to a singlet state absorbing in UV. Though the basic spectral features and kinetics of S2, hot S1, relaxed S1 states remain unchanged upon UV excitation, the clear increase of the S* signal is observed after excess energy excitation, associated with increased S* lifetime. A multiple origin of the S* signal, originating either from specific conformations in the S1 state or from a non-equilibrated ground state, is confirmed in this work. We propose that the increased amount of energy stored in molecular vibrations, induced by the UV excitation, is the reason for the enhanced S* signal observed after UV excitation. Our data also suggest that a fraction of the UV excited state population may proceed through a non-sequential pathway, bypassing the S2 state. 相似文献
7.
用完全活性空间多组态(CASSCF)方法对2-氢吡喃分子光激发开环反应机理进行了研究。利用价键理论(VB)和自然键道分析(NBO)探究了沿能量最低反应途径电子的重新分布情况。计算结果表明从S0-Min p®p*垂直激发到Franck-Condon点后很容易弛豫到S1-Min,经较低的势垒到达圆锥交叉点S1/S0。而S1/S0与S1-Min相比能量低0.63eV。这样体系沿非绝热最低反应途径从激发单重态经交叉点S1/S0很容易得到产物S0-Prod。 相似文献
8.
Mahendra Varne Vaishali Samant Dr. Jahur A. Mondal Dr. Sandip K. Nayak Dr. Hirendra N. Ghosh Dr. Dipak K. Palit Dr. 《Chemphyschem》2009,10(17):2979-2994
The dynamics of the excited states of 1‐aminofluoren‐9‐one (1AF) and 1‐(N,N‐dimethylamino)‐fluoren‐9‐one (1DMAF) are investigated by using steady‐state absorption and fluorescence as well as subpicosecond time‐resolved absorption spectroscopic techniques. Following photoexcitation of 1AF, which exists in the intramolecular hydrogen‐bonded form in aprotic solvents, the excited‐state intramolecular proton‐transfer reaction is the only relaxation process observed in the excited singlet (S1) state. However, in protic solvents, the intramolecular hydrogen bond is disrupted in the excited state and an intermolecular hydrogen bond is formed with the solvent leading to reorganization of the hydrogen‐bond network structure of the solvent. The latter takes place in the timescale of the process of solvation dynamics. In the case of 1DMAF, the main relaxation pathway for the locally excited singlet, S1(LE), or S1(ICT) state is the configurational relaxation, via nearly barrierless twisting of the dimethylamino group to form the twisted intramolecular charge‐transfer, S1(TICT), state. A crossing between the excited‐state and ground‐state potential energy curves is responsible for the fast, radiationless deactivation and nonemissive character of the S1(TICT) state in polar solvents, both aprotic and protic. However, in viscous but strong hydrogen‐bond‐donating solvents, such as ethylene glycol and glycerol, crossing between the potential energy surfaces for the ground electronic state and the hydrogen‐bonded complex formed between the S1(TICT) state and the solvent is possibly avoided and the hydrogen‐bonded complex is weakly emissive. 相似文献
9.
QM/MM Studies on Photoisomerization Dynamics of Azobenzene Chromophore Tethered to a DNA Duplex: Local Unpaired Nucleobase Plays a Crucial Role
下载免费PDF全文
![点击此处可从《化学:亚洲杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dan Wu Ya‐Ting Wang Prof. Dr. Wei‐Hai Fang Prof. Dr. Ganglong Cui Prof. Dr. Walter Thiel 《化学:亚洲杂志》2018,13(7):780-784
The photoresponsive azobenzene‐tethered DNAs have received growing experimental attention because of their potential applications in biotechnology and nanotechnology; however, little is known about the initial photoisomerization of azobenzene in these systems. Herein we have employed quantum mechanics/molecular mechanics (QM/MM) methods to explore the photoisomerization dynamics of an azobenzene‐tethered DNA duplex. We find that in the S1 state the trans–cis photoisomerization path is much steeper in DNA than in vacuo, which makes the photoisomerization much faster in the DNA environment. This acceleration is primarily caused by complex steric interactions between azobenzene and the nearby unpaired thymine nucleobase, which also change the photoisomerization mechanism of azobenzene in the DNA duplex. 相似文献
10.
Azusa Kikuchi Yuki Hata Ryo Kumasaka Yuichi Nanbu Mikio Yagi 《Photochemistry and photobiology》2013,89(3):523-528
The excited states of UV absorber, ethylhexyl methoxycrylene (EHMCR) have been studied through measurements of UV absorption, fluorescence, phosphorescence and electron paramagnetic resonance (EPR) spectra in ethanol. The energy levels of the lowest excited singlet (S1) and triplet (T1) states of EHMCR were determined. The energy levels of the S1 and T1 states of EHMCR are much lower than those of photolabile 4‐tert‐butyl‐4′‐methoxydibenzoylmethane. The energy levels of the S1 and T1 states of EHMCR are lower than those of octyl methoxycinnamate. The weak phosphorescence and EPR Bmin signals were observed and the lifetime was estimated to be 93 ms. These facts suggest that the significant proportion of the S1 molecules undergoes intersystem crossing to the T1 state, and the deactivation process from the T1 state is predominantly radiationless. The photostability of EHMCR arises from the 3ππ* character in the T1 state. The zero‐field splitting (ZFS) parameter in the T1 state is D** = 0.113 cm?1. 相似文献
11.
Mikhayl F. Budyka 《International journal of quantum chemistry》2012,112(14):2643-2649
Potential energy surface (PES) for 1‐styrylnaphthalene was calculated by PM3 method for the S0 state and PM3‐CI(2x2) method with configuration interaction for the S1 state. Scanning PES along both isomerization and cyclization reaction coordinates enabled to reveal the minimum energy path (MEP) with low barriers on the S1 PES from E‐isomer to dihydrocyclophotoproduct (DHP). This is consistent with formation of the photocyclization product in one‐photon process during irradiation of E‐isomer. Additionally, the MEP was found to bypass the coordinate region of Z‐isomer, i.e. one‐photon E‐isomer‐to‐DHP photocyclization does not demand participation of the excited Z‐isomer. Therefore, adiabatic trans‐to‐cis isomerization is likely not an intermediate stage on the E‐isomer photocyclization pathway, and experimentally observed one‐photon formation of the DHP from the E‐isomer is likely not an evidence for adiabatic trans‐to‐cis photoisomerization, as it is usually assumed. According to the results obtained, two photochemical reactions of E‐isomer, photoisomerization to Z‐isomer and photocyclization to DHP, are not consecutive but parallel reactions with branching at perpendicular conformer on the S1 PES. © 2012 Wiley Periodicals, Inc. 相似文献
12.
LiLing Wang Alireza Azizi Roya Momen Tianlv Xu Steven R. Kirk Michael Filatov Samantha Jenkins 《International journal of quantum chemistry》2020,120(1):e26062
Next-generation quantum theory of atoms in molecules was applied to analyze, along an entire bond path, intramolecular interactions known to influence the photoisomerization dynamics of a light-driven rotary molecular motor. The 3D bond-path framework set B0,1 constructed from the least and most preferred directions of electronic motion, provided new insights into the bonding leading to different S1 state lifetimes including the first quantification of covalent character of a closed-shell intramolecular bond path. We undertook the first use of the stress tensor trajectory Tσ(s) analysis on selected nonadiabatic molecular dynamics trajectories with the electron densities obtained using the ensemble density functional theory method. The stress tensor Tσ(s) analysis was found to be well suited to follow the dynamics trajectories that included the S0 and S1 electronic states through the conical intersection and also provided to a new measure to assess the degree of purity of the axial bond rotation for the design of rotary molecular motors. 相似文献
13.
《International journal of quantum chemistry》2018,118(16)
The photoinduced isomerization of cis‐keto and trans‐keto isomers in N‐salicilydenemethylfurylamine has been studied using the surface‐hopping approach at the CASSCF level of theory. After the cis‐keto or trans‐keto isomer is excited to S1 state, the molecule initially moves to a excited‐state local minimum. The torsional motion around relative bonds in the chain drives the molecule to approach a keto‐form conical intersection and then nonadiabatic transition occurs. According to our full‐dimensional dynamics simulations, the trans‐keto and enol photoproducts are responsible for the photochromic effect of cis‐keto isomer excited to S1 state, while no enol isomer was obtained in the photoisomerization of trans keto on excitation. The cis keto to enol and cis keto to trans keto isomerizations are reversible photochemical reactions. It is confirmed that this aromatic Schiff base is a potential molecular switch. Furthermore, the torsion of C N bond occurs in the radiationless decay of trans‐keto isomer, while it is completely suppressed by an intramolecular hydrogen bonding interaction in the dynamics of cis‐keto form. Moreover, the excited‐state lifetime of cis keto is longer than that of trans‐keto form due to the O···H N hydrogen bond. 相似文献
14.
Jahur A. Mondal Dr. Vaishali Samant Dr. Mahendra Varne Ajay K. Singh Dr. Tapan K. Ghanty Dr. Hirendra N. Ghosh Dr. Dipak K. Palit Dr. 《Chemphyschem》2009,10(17):2995-3012
The dynamics of the excited states of 3‐ and 4‐aminofluoren‐9‐ones (3AF and 4AF, respectively) are investigated in different kinds of solvents by using a subpicosecond time‐resolved absorption spectroscopic technique. They undergo hydrogen‐bonding interaction with protic solvents in both the ground and excited states. However, this interaction is more significant in the lowest excited singlet (S1) state because of its substantial intramolecular charge‐transfer character. Significant differences in the spectroscopic characteristics and temporal dynamics of the S1 states of 3AF and 4AF in aprotic and protic solvents reveal that the intermolecular hydrogen‐bonding interaction between the S1 state and protic solvents plays an important role in its relaxation process. Perfect linear correlation between the relaxation times of the S1 state and the longitudinal relaxation times (τL) of alcoholic solvents confirms the prediction regarding the solvation process via hydrogen‐bond reorganization. In the case of weakly interacting systems, the relaxation process can be well described by a dipolar solvation‐like process involving rotation of the OH groups of the alcoholic solvents, whereas in solvents having a strong hydrogen‐bond‐donating ability, for example, methanol and trifluoroethanol, it involves the conversion of the non‐hydrogen‐bonded form to the hydrogen‐bonded complex of the S1 state. Efficient radiationless deactivation of the S1 state of the aminofluorenones by protic solvents is successfully explained by the energy‐gap law, by using the energy of the fully solvated S1 state determined from the time‐resolved spectroscopic data. 相似文献
15.
Jahur A. Mondal Sandeep Verma Hirendra N. Ghosh Dipak K. Palit 《Journal of Chemical Sciences》2008,120(1):45-55
Relaxation dynamics of the excited singlet states of 2,5-bis-(N-methyl-N-1,3-propdienylaniline)-cyclopentanone (MPAC), a ketocyanine dye, have been investigated using steady-state absorption
and emission as well as femtosecond time-resolved absorption spectroscopic techniques. Following photoexcitation using 400
nm light, the molecule is excited to the S2 state, which is fluorescent in rigid matrices at 77 K. S2 state is nearly non-fluorescent in solution and has a very short lifetime (0.5 ± 0.2 ps). In polar aprotic solvents, the
S1 state follows a complex multi-exponential relaxation dynamics consisting of torsional motion of the donor groups, solvent
re-organization as well as photoisomerization processes. However, in alcoholic solvents, solvent re-organization via intermolecular
hydrogen-bonding interaction is the only relaxation process observed in the S1 state. In trifluoroethanol, a strong hydrogen bonding solvent, conversion of the non-hydrogen-bonded form, which is formed
following photoexcitation, to the hydrogen-bonded complex has been clearly evident in the relaxation process of the S1 state. 相似文献
16.
The photostabilizing ability of grape seed extract on three common sunscreen absorbers, 2‐ethylhexyl‐p‐methoxycinnamate (EHMC), benzophenone‐3 (BP3) and tert‐butylmethoxy dibenzoylmethane (BMDBM), was investigated. Samples were exposed to simulated solar radiation and monitored by spectrophotometric and chromatographic methods. The chemical composition of the grape seed extract was determined by GC‐MS and HPLC‐MS, and the major secondary metabolites were found to be epicatechin and catechin. Exposure of the extract to UV radiation increased the UV absorption capacity of the extract. All sunscreens showed an improved photostability in the extract. The inherent photo‐instability of BMDBM when exposed to UV radiation was almost eliminated in the presence of grape seed extract. A mixture of all three sunscreens in the extract showed very high photostability and a red shift covering the entire UVB and UVA regions, thereby improving the broad‐spectrum protection. The incorporation of grape seed extract in sunscreen and other cosmetic formulations for topical application boosts photoprotection by stabilizing the UV filters and enhancing broad‐spectrum coverage. This in turn helps in reducing the amounts of absorbers and other additives incorporated in a sunscreen product and consequently lowers the risk of an unprecedented buildup of photoproducts whose toxicities are currently unknown. 相似文献
17.
Mechanism for the Nonadiabatic Photooxidation of Benzene to Phenol: Orientation‐Dependent Proton‐Coupled Electron Transfer
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Xue‐Ping Chang Prof. Dr. Ganglong Cui Prof. Dr. Wei‐Hai Fang Prof. Dr. Walter Thiel 《Chemphyschem》2015,16(5):933-937
An efficient catalytic one‐step conversion of benzene to phenol was achieved recently by selective photooxidation under mild conditions with 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone (DDQ) as the photocatalyst. Herein, high‐level electronic structure calculations in the gas phase and in acetonitrile solution are reported to explore the underlying mechanism. The initially populated 1ππ* state of DDQ can relax efficiently through a nearby dark 1nπ* doorway state to the 3ππ* state of DDQ, which is found to be the precursor state involved in the initial intermolecular electron transfer from benzene to DDQ. The subsequent triplet‐state reaction between DDQ radical anions, benzene radical cations, and water is computed to be facile. The formed DDQH and benzene‐OH radicals can undergo T1→S0 intersystem crossing and concomitant proton‐coupled electron transfer (PCET) to generate the products DDQH2 and phenol. Two of the four considered nonadiabatic pathways involve an orientation‐dependent triplet PCET process, followed by intersystem crossing to the ground state (S0). The other two first undergo a nonadiabatic T1→S0 transition to produce a zwitterionic S0 complex, followed by a barrierless proton transfer. The present theoretical study identifies novel types of nonadiabatic PCET processes and provides detailed mechanistic insight into DDQ‐catalyzed photooxidation. 相似文献
18.
Dr. Theis I. Sølling Dr. Thomas S. Kuhlman Anne B. Stephansen Liv B. Klein Dr. Klaus B. Møller 《Chemphyschem》2014,15(2):249-259
The absorption of light by molecules can induce ultrafast dynamics and coupling of electronic and nuclear vibrational motion. The ultrafast nature in many cases rests on the importance of several potential energy surfaces in guiding the nuclear motion—a concept of central importance in many aspects of chemical reaction dynamics. This Minireview focuses on the non‐ergodic nature of internal conversion, that is, on the concept that the nuclear dynamics only sample a reduced phase space, potentially resulting in localization of the dynamics in real space. A series of results that highlight the nonstatistical nature of the excited‐state deactivation process is presented. The examples are categorized into four groups. 1) Localization of the energy in one degree of freedom in S2→S1 transitions, in which the transition is either determined by the time spent in the S2→S1 coupling region or by the time it takes to reach it. 2) Localization of energy into a single reactive mode, which is dictated by the internal conversion process. 3) Initiation of the internal conversion by activation of a single complex motion, which then specifically couples to a reactive mode. 4) Nonstatistical internal conversion as a tool to accomplish biomolecular stability. Herein, the discussion on nonstatistical internal conversion in DNA as a mechanism to eliminate electronic excitation energy is extended to include molecules with an S?S bond as a model of the disulfide bridge in peptides. All of these examples are summed up in Kasha’s rule. For systems with multiple degrees of freedom it will be possible to locate an appropriate motion somewhere in phase space that will take the wavepacket to the coupling region and facilitate an ultrafast transition to S1. Once at S1, the momentum of the wavepacket is lost and the only options left are the statistical processes of reaction or light emission. 相似文献
19.
Bodhisatwa Mondal Dr. Rajesh Bera Srijon Ghosh Dr. Sandip K. Nayak Prof. Amitava Patra 《Chemphyschem》2020,21(19):2196-2205
Here, we have synthesized rod and flake shaped morphology of porphyrin aggregates from 5, 10, 15, 20-tetra (4-n-octyloxyphenyl) porphyrin (4-opTPP) molecule which are evident from scanning electron microscopy (SEM). The formation of J-type aggregation is evident from steady state and time-resolved fluorescence spectroscopic studies. Ultrafast transient absorption spectroscopic studies reveal that the excited state lifetime is controlled by the morphology and the time constant for S1→S0 relaxation changes from 3.05 ps to 744 ps with changing the shape from rod to flake, respectively. In spite of similar exciton coupling energy in both the aggregates, the flake shaped aggregates undergo a faster exciton relaxation process and the non-radiative relaxation channels are found to depend on the shape of aggregates. The fundamental understanding of morphology controlled ultrafast relaxation processes of aggregated porphyrin is important for designing efficient light harvesting devices. 相似文献
20.
Solar UV Irradiances Modulate Effects of Ocean Acidification on the Coccolithophorid Emiliania huxleyi
下载免费PDF全文
![点击此处可从《Photochemistry and photobiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Emiliania huxleyi, the most abundant coccolithophorid in the oceans, is naturally exposed to solar UV radiation (UVR, 280–400 nm) in addition to photosynthetically active radiation (PAR). We investigated the physiological responses of E. huxleyi to the present day and elevated CO2 (390 vs 1000 μatm; with pHNBS 8.20 vs 7.86) under indoor constant PAR and fluctuating solar radiation with or without UVR. Enrichment of CO2 stimulated the production rate of particulate organic carbon (POC) under constant PAR, but led to unchanged POC production under incident fluctuating solar radiation. The production rates of particulate inorganic carbon (PIC) as well as PIC/POC ratios were reduced under the elevated CO2, ocean acidification (OA) condition, regardless of PAR levels, and the presence of UVR. However, moderate levels of UVR increased PIC production rates and PIC/POC ratios. OA treatment interacted with UVR to influence the alga's physiological performance, leading to reduced specific growth rate in the presence of UVA (315–400 nm) and decreased quantum yield, along with enhanced nonphotochemical quenching, with addition of UVB (280–315 nm). The results clearly indicate that UV radiation needs to be invoked as a key stressor when considering the impacts of ocean acidification on E. huxleyi. 相似文献