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Moritaka SS, Lebedev VS. Orientational effects in the polarized absorption spectra of molecular aggregates. J Chem Phys 2024; 160:074901. [PMID: 38364011 DOI: 10.1063/5.0188128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/23/2024] [Indexed: 02/18/2024] Open
Abstract
We present a detailed theoretical analysis of polarized absorption spectra and linear dichroism of cyanine dye aggregates whose unit cells contain two molecules. The studied threadlike ordered system with a molecular exciton delocalized along its axis can be treated as two chains of conventional molecular aggregates, rotated relative to each other at a certain angle around the aggregate axis. Our approach is based on the general formulas for the effective cross section of light absorption by a molecular aggregate and key points of the molecular exciton theory. We have developed a self-consistent theory for describing the orientational effects in the absorption and dichroic spectra of such supramolecular structures with nonplanar unit cell. It is shown that the spectral behavior of such systems exhibits considerable distinctions from that of conventional cyanine dye aggregates. They consist in the strong dependence of the relative intensities of the J- and H-type spectral bands of the aggregate with a nonplanar unit cell on the angles determining the mutual orientations of the transition dipole moments of constituting molecules and the aggregate axis as well as on the polarization direction of incident light. The derived formulas are reduced to the well-known analytical expressions in the particular case of aggregates with one molecule in the unit cell. The calculations performed within the framework of our excitonic theory combined with available vibronic theory allow us to quite reasonably explain the experimental data for the pseudoisocyanine bromide dye aggregate.
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Affiliation(s)
- S S Moritaka
- P. N. Lebedev Physical Institute of Russian Academy of Sciences, 53 Leninskiy Prosp., 119991 Moscow, Russian Federation
| | - V S Lebedev
- P. N. Lebedev Physical Institute of Russian Academy of Sciences, 53 Leninskiy Prosp., 119991 Moscow, Russian Federation
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2
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Somasundaran SM, Kompella SVK, Mohan T M N, Das S, Abdul Vahid A, Vijayan V, Balasubramanian S, Thomas KG. Structurally Induced Chirality of an Achiral Chromophore on Self-Assembled Nanofibers: A Twist Makes It Chiral. ACS NANO 2023. [PMID: 37220308 DOI: 10.1021/acsnano.3c03892] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The surface domains of self-assembled amphiphiles are well-organized and can perform many physical, chemical, and biological functions. Here, we present the significance of chiral surface domains of these self-assemblies in transferring chirality to achiral chromophores. These aspects are probed using l- and d-isomers of alkyl alanine amphiphiles which self-assemble in water as nanofibers, possessing a negative surface charge. When bound on these nanofibers, positively charged cyanine dyes (CY524 and CY600), each having two quinoline rings bridged by conjugated double bonds, show contrasting chiroptical features. Interestingly, CY600 displays a bisignated circular dichroic (CD) signal with mirror-image symmetry, while CY524 is CD silent. Molecular dynamics simulations reveal that the model cylindrical micelles (CM) derived from the two isomers exhibit surface chirality and the chromophores are buried as monomers in mirror-imaged pockets on their surfaces. The monomeric nature of template-bound chromophores and their binding reversibility are established by concentration- and temperature-dependent spectroscopies and calorimetry. On the CM, CY524 displays two equally populated conformers with opposite sense, whereas CY600 is present as two pairs of twisted conformers in each of which one is in excess, due to differences in weak dye-amphiphile hydrogen bonding interactions. Infrared and NMR spectroscopies support these findings. Reduction of electronic conjugation caused by the twist establishes the two quinoline rings as independent entities. On-resonance coupling between the transition dipoles of these units generates bisignated CD signals with mirror-image symmetry. The results presented herein provide insight on the little-known structurally induced chirality of achiral chromophores through transfer of chiral surface information.
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Affiliation(s)
- Sanoop Mambully Somasundaran
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Srinath V K Kompella
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore 560064, India
| | - Nila Mohan T M
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Sudip Das
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore 560064, India
| | - Arshad Abdul Vahid
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Vinesh Vijayan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Sundaram Balasubramanian
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore 560064, India
| | - K George Thomas
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
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Ma F. Dynamics and Coherent Control of Exciton–Exciton Annihilation in Aqueous J-Aggregate. J Phys Chem B 2018; 122:10746-10753. [DOI: 10.1021/acs.jpcb.8b09891] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fei Ma
- Division of Chemical Physics, Department of Chemistry, Lund University, 221 00 Lund, Sweden
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Magana JR, Solans C, Salonen LM, Carbó-Argibay E, Gallo J, Tiddy GJ, Rodríguez-Abreu C. Chromonic self-assemblies in a series of dialkyl-thiacarbocyanine dyes and generalization of a facile route for the synthesis of fluorescent nanostructured silica fibers. J Taiwan Inst Chem Eng 2018. [DOI: 10.1016/j.jtice.2018.03.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Das K, Hazra B, Chandra M. Exploring the coherent interaction in a hybrid system of hollow gold nanoprisms and cyanine dye J-aggregates: role of plasmon-hybridization mediated local electric-field enhancement. Phys Chem Chem Phys 2017; 19:27997-28005. [DOI: 10.1039/c7cp05455f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this work, we probed the possibility of observing strong plasmon–exciton interactions in hollow gold nanoprism–J-aggregate nanocomposites.
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Affiliation(s)
- Kamalika Das
- Department of Chemistry, Indian Institute of Technology
- Kanpur
- India
| | - Bidhan Hazra
- Department of Chemistry, Indian Institute of Technology
- Kanpur
- India
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Ma F, Yartsev A. Ultrafast photoisomerization of pinacyanol: watching an excited state reaction transiting from barrier to barrierless forms. RSC Adv 2016. [DOI: 10.1039/c6ra03299k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photoisomerization of 1,1′-diethyl-2,2′-carbocyanine iodide (pinacyanol) in alcohols was investigated by means of femtosecond time-resolved absorption spectroscopy.
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Affiliation(s)
- Fei Ma
- Chemical Physics
- Department of Chemistry
- Lund University
- Lund
- Sweden
| | - Arkady Yartsev
- Chemical Physics
- Department of Chemistry
- Lund University
- Lund
- Sweden
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Aydin M. Comparative study of the structural and vibroelectronic properties of porphyrin and its derivatives. Molecules 2014; 19:20988-1021. [PMID: 25517340 PMCID: PMC6271358 DOI: 10.3390/molecules191220988] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 11/26/2022] Open
Abstract
Density functional theory (DFT and time-dependent-DFT (TD-DFT) were employed to investigate the vibroelectronic structural properties of porphyrin and some derivatives: unsubstituted porphyrin (TPyr), meso-tetraphenylporphyrin (TPP), meso-tetrakis(p-sulfonatophenyl)porphyrin (TSPP), protonated-TPyr (H2TPyr), deuterated-H2TPyr (D4TPyr), protonated-TPP (H2TPP) and deuterated-H2TPP (D4TPP), protonated TSPP (H2TSPP), deuterated-H2TSPP (D4TSPP), dicationic TSPP (H6TSPP) and deuterated-H6TSPP (D8TSPP). The possible internal conversion (IC) and intersystem crossing (ISC) processes of these compounds were investigated. Finally, the relaxed ground state potential energy surface (PES) (S0), and singlet (Sn, n = 1–24) and triplet (Tn) excited state PESs of the TSPP molecule were calculated as function of the dihedral angle (Cα-Cm-Cϕ-C(ph)) rotation. The results of the calculations indicated that while the meso-substitutions caused a significant shift in frequencies when the meso-carbons within the parent-porphine (or TPyr) are involved in the vibrational motion of molecules; the protonation of the N atoms at the porphine/porphyrin core causes a significant blue shift when the H on the N atoms within the pyrroline are dominantly involved in the vibrational motions. The deuteration of N atoms not only caused a red-shift in the frequencies of the corresponding peaks below 1600 cm−1, but also produced new vibrational modes of frequencies in the 2565–2595 cm−1 range caused by the N-D bond stretching. Similarly, the deuteration of O atoms within the sulfonato groups (-SO3−) exhibited a new peak at around 2642 cm−1 due to O-D bond stretching. The measured Raman spectrum of the H2TSPP is assigned based on the predicted Raman spectra of the compounds studied here and measured Raman spectrum of the TPP (from our previous work). The IR spectrum is assigned based on our calculations and measured IR spectra obtained from the literature. The results of the TD-DFT calculations did not only indicate that the meso-substitution and protonation of the porphyrin bring about a significant read shift in the electronic transitions; but also provided a strong evidence for the IC from the Soret band to Q-bands beside possibility of the ISC process; its existence depend on the other excited state process such as much faster vibrational relaxation; the IC and etc. The ground state PES curve (S0) of the ionic TSPP exhibited two minima at the dihedral angle (Cα-Cm-Cϕ-C) of about 66° (corresponds to the lowest ground state) and 110° (corresponds to next energetically stable state or the local minima). The energy deference between these two minima is 0.0132 eV (or 106 cm−1) and the highest potential energy barrier when undergoing from the lowest ground state to this local state is only 0.0219 eV (177 cm−1; which is compatible with the thermal energy (kT) at 298 K is 207.2 cm−1.
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Affiliation(s)
- Metin Aydin
- Department of Chemistry, Faculty of Art and Sciences, Ondokuz Mayıs University, Samsun 55139, Turkey.
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Krpetić Z, Guerrini L, Larmour IA, Reglinski J, Faulds K, Graham D. Importance of nanoparticle size in colorimetric and SERS-based multimodal trace detection of Ni(II) ions with functional gold nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:707-714. [PMID: 22223552 DOI: 10.1002/smll.201101980] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Indexed: 05/31/2023]
Abstract
Colorimetric detection of analytes using gold nanoparticles along with surface-enhanced Raman spectroscopy (SERS) are areas of intense research activity since they both offer sensing of very low concentrations of target species. Multimodal detection promotes the simultaneous detection of a sample by a combination of different techniques; consequently, surface chemistry design in the development of multimodal nanosensors is important for rapid and sensitive evaluation of the analytes by diverse analytical methods. Herein it is shown that nanoparticle size plays an important role in the design of functional nanoparticles for colorimetric and SERS-based sensing applications, allowing controlled nanoparticle assembly and tunable sensor response. The design and preparation of robust nanoparticle systems and their assembly is reported for trace detection of Ni(II) ions as a model system in an aqueous solution. The combination of covalently attached nitrilotriacetic acid moieties along with the L-carnosine dipeptide on the nanoparticle surface represents a highly sensitive platform for rapid and selective detection of Ni(II) ions. This systematic study demonstrates that significantly lower detection limits can be achieved by finely tuning the assembly of gold nanoparticles of different core sizes. The results clearly demonstrate the feasibility and usefulness of a multimodal approach.
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Affiliation(s)
- Zeljka Krpetić
- Centre for Molecular Nanometrology, WestCHEM, Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
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Melnikau D, Savateeva D, Chuvilin A, Hillenbrand R, Rakovich YP. Whispering gallery mode resonators with J-aggregates. OPTICS EXPRESS 2011; 19:22280-22291. [PMID: 22109070 DOI: 10.1364/oe.19.022280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have studied the optical properties of a hybrid system consisting of cyanine dye J-aggregates attached to a spherical microcavity. A periodic structure of narrow peaks was observed in the photoluminescence spectrum of the J-aggregates, arising from the coupling between the emission of J-aggregates and the whispering gallery modes (WGMs) of the microcavity. The most striking result of our study is the observation of polarization sensitive mode damping caused by re-absorption of J-aggregate emission. This effect manifests itself in dominating emission from TM modes in the spectral region of J-aggregates absorption band where the TE modes are strongly suppressed. In contrast, the TE modes totally dominate emission spectrum in the region where absorption is negligible. We also demonstrate that the emission intensity can be further enhanced by depositing a hybrid layer of J-aggregates and Ag nanoparticles onto the spherical microcavity. Owing to the concerted action of WGMs and plasmonic hot spots in the Ag aggregates, we observe an enhanced Raman signal from the J-aggregates. Microcavities covered by J-aggregates and plasmonic nanoparticles could be thus useful for a variety of photonic applications in basic science and technology.
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Affiliation(s)
- Dzmitry Melnikau
- CIC nanoGune Consolider, Tolosa Hiribidea 76, Donostia-San-Sebastian, 20018, Spain
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10
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Aydin M, Dede Ö, Akins DL. Density functional theory and Raman spectroscopy applied to structure and vibrational mode analysis of 1,1',3,3'-tetraethyl-5,5',6,6'-tetrachloro- benzimidazolocarbocyanine iodide and its aggregate. J Chem Phys 2011; 134:064325. [PMID: 21322698 DOI: 10.1063/1.3535595] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We have measured electronic and Raman scattering spectra of 1,1',3,3'-tetraethyl-5,5',6,6'-tetrachloro-benzimidazolocarbocyanine iodide (TTBC) in various environments, and we have calculated the ground state geometric and spectroscopic properties of the TTBC cation in the gas and solution phases (e.g., bond distances, bond angles, charge distributions, and Raman vibrational frequencies) using density functional theory. Our structure calculations have shown that the ground state equilibrium structure of a cis-conformer lies ∼200 cm(-1) above that of a trans-conformer and both conformers have C(2) symmetry. Calculated electronic transitions indicate that the difference between the first transitions of the two conformers is about 130 cm(-1). Raman spectral assignments of monomeric- and aggregated-TTBC cations have been aided by density functional calculations at the same level of the theory. Vibrational mode analyses of the calculated Raman spectra reveal that the observed Raman bands above 700 cm(-1) are mainly associated with the in-plane deformation of the benzimidazolo moieties, while bands below 700 cm(-1) are associated with out-of-plane deformations of the benzimidazolo moieties. We have also found that for the nonresonance excited experimental Raman spectrum of aggregated-TTBC cation, the Raman bands in the higher-frequency region are enhanced compared with those in the nonresonance spectrum of the monomeric cation. For the experimental Raman spectrum of the aggregate under resonance excitation, however, we find new Raman features below 600 cm(-1), in addition to a significantly enhanced Raman peak at 671 cm(-1) that are associated with out-of-plane distortions. Also, time-dependent density functional theory calculations suggest that the experimentally observed electronic transition at ∼515 nm (i.e., 2.41 eV) in the absorption spectrum of the monomeric-TTBC cation predominantly results from the π → π∗ transition. Calculations are further interpreted as indicating that the observed shoulder in the absorption spectrum of TTBC in methanol at 494 nm (i.e., 2.51 eV) likely results from the ν(") = 0 → ν' = 1 transition and is not due to another electronic transition of the trans-conformer-despite the fact that measured and calculated NMR results (not provided here) support the prospect that the shoulder might be attributable to the 0-0 band of the cis-conformer.
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Affiliation(s)
- Metin Aydin
- Department of Chemistry, Faculty of Art and Sciences, Ondokuz Mayıs University, 55139 Samsun, Turkey.
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11
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Coles DM, Meijer AJHM, Tsoi WC, Charlton MDB, Kim JS, Lidzey DG. A Characterization of the Raman Modes in a J-Aggregate-Forming Dye: A Comparison between Theory and Experiment. J Phys Chem A 2010; 114:11920-7. [DOI: 10.1021/jp107646p] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David M. Coles
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K., Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Department of Physics, Imperial College, London SW7 2AZ, U.K., and School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, U.K
| | - Anthony J. H. M. Meijer
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K., Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Department of Physics, Imperial College, London SW7 2AZ, U.K., and School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, U.K
| | - Wing C. Tsoi
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K., Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Department of Physics, Imperial College, London SW7 2AZ, U.K., and School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, U.K
| | - Martin D. B. Charlton
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K., Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Department of Physics, Imperial College, London SW7 2AZ, U.K., and School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, U.K
| | - Ji-Seon Kim
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K., Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Department of Physics, Imperial College, London SW7 2AZ, U.K., and School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, U.K
| | - David G. Lidzey
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K., Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Department of Physics, Imperial College, London SW7 2AZ, U.K., and School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, U.K
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Mo GCH, Yip CM. Supported lipid bilayer templated J-aggregate growth: role of stabilizing cation-pi interactions and headgroup packing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10719-10729. [PMID: 19645500 DOI: 10.1021/la901227h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Controlling the self-assembly of molecules into specific structural motifs has important implications for the design of materials with specific optical properties. We report here the results of a correlated confocal fluorescence-atomic force microscopy (AFM) study of pseudoisocyanine iodide (PIC) self-assembly on supported lipid bilayers. Through judicious selection of bilayer headgroup packing and chemistry, two types of PIC J-aggregates, distinguishable by their absorbance spectra, and both exhibiting strong resonant fluorescence and bathochromic shifts in absorbance relative to the monomer, were isolated. Remarkably, selective templating can be achieved using different zwitterionic headgroups, producing J-aggregates that display a larger bathochromic shift than their solution counterparts. Our correlated confocal-AFM studies coupled with FT-IR spectroscopy suggested that zwitterionic phospholipids mediate J-aggregate formation through specific cation-pi interactions between PIC and the lipid headgroups with the PIC molecules oriented largely perpendicular to the bilayer normal. The existence of the two isoforms further suggests that bilayer headgroup packing plays a key role in controlling interchromophore organization and subsequent aggregate nucleation and growth.
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Affiliation(s)
- Gary C H Mo
- Department of Biochemistry, Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
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Dietzek B, Tarnovsky AN, Yartsev A. Visualizing overdamped wavepacket motion: Excited-state isomerization of pseudocyanine in viscous solvents. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2008.10.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dietzek B, Brüggemann B, Persson P, Yartsev A. On the excited-state multi-dimensionality in cyanines. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dietzek B, Pascher T, Yartsev A. Tracking Ultrafast Excited-State Bond-Twisting Motion in Solution Close to the Franck−Condon Point. J Phys Chem B 2007; 111:6034-41. [PMID: 17480068 DOI: 10.1021/jp068652i] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Applying optimal control to photoinduced trans-cis isomerization in condensed phase, the dynamics of bond-twisting motion of 1,1'-diethyl-4,4'-cyanine in methanol and propanol is revealed. The shape of the optimized pulse resulting from minimization of the photoisomer formation can be directly related to the initial excited-state dynamics in close proximity to the Franck-Condon point. The solvent viscosity-dependent ultrafast wavepacket motion is reflected in the prominent down-chirp of the optimized pulses and reveals a detailed picture of the control mechanism: The reduction of the isomer production is achieved by most efficient dumping of excited population back to the trans ground state. In the higher-viscosity solvent, propanol, wavelength-dependent oscillatory features are superimposed to the overall chirp structure pointing to the importance of excited-state vibrational coherences for the dumping process.
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Affiliation(s)
- Benjamin Dietzek
- Department of Chemical Physics, Lund University, Lund, Sweden. dietzek@ mit.edu
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Dietzek B, Yartsev A, Tarnovsky AN. Watching Ultrafast Barrierless Excited-State Isomerization of Pseudocyanine in Real Time. J Phys Chem B 2007; 111:4520-6. [PMID: 17417893 DOI: 10.1021/jp066471a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The photoinduced excited-state processes in 1,1'-diethyl-2,2'-cyanine iodine are investigated using femtosecond time-resolved pump-probe spectroscopy. Using a broad range of probe wavelengths, the relaxation of the initially prepared excited-state wavepacket can be followed down to the sink region. The data directly visualize the directed downhill motion along the torsional reaction coordinate and suggest a barrierless excited-state isomerization in the short chain cyanine dye. Additionally, ultrafast ground-state hole and excited-state hole replica broadening is observed. While the narrow excited-state wavepacket broadens during pump-probe overlap, the ground-state hole burning dynamics takes place on a significantly longer time-scale. The experiment reported can be considered as a direct monitoring of the shape and the position of the photoprepared wavepacket on the excited-state potential energy surface.
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Affiliation(s)
- Benjamin Dietzek
- Department of Chemical Physics, Lund University, P.O. Box 124, 22100 Lund, Sweden
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Dietzek B, Brüggemann B, Pascher T, Yartsev A. Mechanisms of molecular response in the optimal control of photoisomerization. PHYSICAL REVIEW LETTERS 2006; 97:258301. [PMID: 17280400 DOI: 10.1103/physrevlett.97.258301] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Indexed: 05/13/2023]
Abstract
We report on adaptive feedback control of photoinduced barrierless isomerization of 1,1'-diethyl-2,2'-cyanine in solution. We compare the effect of different fitness parameters and show that optimal control of the absolute yield of isomerization (photoisomer concentration versus excitation photons) can be achieved, while the relative isomerization yield (photoisomer concentration versus number of relaxed excited-state molecules) is unaffected by adaptive feedback control. The temporal structure of the optimized excitation pulses allows one to draw clear mechanistic conclusions showing the critical importance of coherent nuclear motion for the control of isomerization.
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Affiliation(s)
- Benjamin Dietzek
- Department of Chemical Physics, Lund University, PO Box 124, 22100 Lund, Sweden.
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Kobayashi T, Nishimura K, Tokunaga E. Real-time spectroscopy of pseudoisocyanine J-aggregates with sub-5fs lasers. J Mol Struct 2005. [DOI: 10.1016/j.molstruc.2004.11.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Aydin M, Jean-Mary F, Stevens N, Akins DL. Density Functional Theory Applied to Structure and Vibrational Band Analysis of an Aggregated Thiacarbocyanine. J Phys Chem B 2004. [DOI: 10.1021/jp037678w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Metin Aydin
- Center for Analysis of Structures and Interfaces (CASI), Department of Chemistry, The City College of The City University of New York, New York, New York 10031
| | - Fleumingue Jean-Mary
- Center for Analysis of Structures and Interfaces (CASI), Department of Chemistry, The City College of The City University of New York, New York, New York 10031
| | - Nathan Stevens
- Center for Analysis of Structures and Interfaces (CASI), Department of Chemistry, The City College of The City University of New York, New York, New York 10031
| | - Daniel L. Akins
- Center for Analysis of Structures and Interfaces (CASI), Department of Chemistry, The City College of The City University of New York, New York, New York 10031
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Myers Kelley A. A multimode vibronic treatment of absorption, resonance Raman, and hyper-Rayleigh scattering of excitonically coupled molecular dimers. J Chem Phys 2003. [DOI: 10.1063/1.1588995] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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