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Jianping Wang - One of the best experts on this subject based on the ideXlab platform.
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ultrafast intermolecular Vibrational Energy transfer in hexahydro 1 3 5 trinitro 1 3 5 triazine in molecular crystal by 2d ir spectroscopy
Journal of Physical Chemistry C, 2020Co-Authors: Lu Shi, Juan Zhao, Jianping WangAbstract:Cyclic nitramine hexahydro-1,3,5-trinitro-s-triazine (HHTT) is an important energetic molecule with a variety of applications. In this work, structural dynamics and Vibrational-Energy transfer dyna...
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ultrafast intermolecular Vibrational Energy transfer in hexahydro 1 3 5 trinitro 1 3 5 triazine in molecular crystal by 2d ir spectroscopy
The Journal of Physical Chemistry, 2020Co-Authors: Pengyun Yu, Juan Zhao, Jianping WangAbstract:Cyclic nitramine hexahydro-1,3,5-trinitro-s-triazine (HHTT) is an important energetic molecule with a variety of applications. In this work, structural dynamics and Vibrational-Energy transfer dynamics of HHTT were investigated using steady-state infrared (IR), femtosecond time-resolved IR, and two-dimensional (2D) IR spectroscopic methods. Two different structural forms of HHTT (isolated molecules dissolved in DMSO and microcrystal dispersed in paraffin oil) were examined using the NO₂ asymmetric stretching mode as a structural marker. Both intra- and intermolecular Vibrational Energy transfers were observed in HHTT microcrystal, where the well-known α-conformation was retained. However, less perfect α-HHTT species was found in DMSO. An intermolecular Energy dissipation pathway was found to be related to Davydov splitting in the microcrystal form of HHTT, which originates from intermolecular interactions (e.g., electrostatic and hydrogen bonds). Experimental results were supported by quantum-chemistry computations. In addition, both Vibrational excited-state relaxation and Vibrational Energy-transfer processes were found to be more efficient in HHTT microcrystal than in the solvated form. Our work provides a chemical-bond level of insight into the nitro group-containing energetic materials.
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ultrafast intramolecular Vibrational Energy transfer in carbon nitride hydrocolloid examined by femtosecond two dimensional infrared spectroscopy
Journal of Chemical Physics, 2019Co-Authors: Xuan Zheng, Jianping WangAbstract:In this work, ultrafast Vibrational and structural processes in a graphitic carbon nitride hydrocolloid system were studied using a combination of linear infrared and nonlinear two-dimensional infrared (2D IR) spectroscopies. The experimentally observed three IR line shapes in the C=N stretching vibration frequency region were analyzed and attributed to the rigid and conjugated molecular frame of the prepared g-CN molecular species, which is believed to be a dimeric tris-s-triazine, as well as attributed to insignificant solvent influence on the delocalized C=N vibrations. Vibrational transition density cubes were also computed for the proposed g-CN dimer, confirming the heterocyclic C=N stretching nature of the three IR absorption peaks. Intramolecular Vibrational Energy transfer dynamics and spectral diffusion of the g-CN system were characterized by examining a series of time-dependent 2D IR spectra. A picosecond intramolecular Vibrational Energy redistribution process was found to occur among these delocalized C=N stretching modes, acting as an efficient Vibrational Energy transfer channel. This work reasonably connects the experimentally observed IR signature to a specific g-CN structure and also provides the first report on the ultrafast intramolecular processes of such carbon nitride systems. The obtained results are fundamentally important for understanding the molecular mechanisms of such carbon-nitride based functional materials.
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ultrafast intramolecular Vibrational Energy transfer in carbon nitride hydrocolloid examined by femtosecond two dimensional infrared spectroscopy
Journal of Chemical Physics, 2019Co-Authors: Xuan Zheng, Pengyun Yu, Jianping WangAbstract:In this work, ultrafast Vibrational and structural processes in a graphitic carbon nitride hydrocolloid system were studied using a combination of linear infrared and nonlinear two-dimensional infrared (2D IR) spectroscopies. The experimentally observed three IR line shapes in the C=N stretching vibration frequency region were analyzed and attributed to the rigid and conjugated molecular frame of the prepared g-CN molecular species, which is believed to be a dimeric tris-s-triazine, as well as attributed to insignificant solvent influence on the delocalized C=N vibrations. Vibrational transition density cubes were also computed for the proposed g-CN dimer, confirming the heterocyclic C=N stretching nature of the three IR absorption peaks. Intramolecular Vibrational Energy transfer dynamics and spectral diffusion of the g-CN system were characterized by examining a series of time-dependent 2D IR spectra. A picosecond intramolecular Vibrational Energy redistribution process was found to occur among these delocalized C=N stretching modes, acting as an efficient Vibrational Energy transfer channel. This work reasonably connects the experimentally observed IR signature to a specific g-CN structure and also provides the first report on the ultrafast intramolecular processes of such carbon nitride systems. The obtained results are fundamentally important for understanding the molecular mechanisms of such carbon-nitride based functional materials.In this work, ultrafast Vibrational and structural processes in a graphitic carbon nitride hydrocolloid system were studied using a combination of linear infrared and nonlinear two-dimensional infrared (2D IR) spectroscopies. The experimentally observed three IR line shapes in the C=N stretching vibration frequency region were analyzed and attributed to the rigid and conjugated molecular frame of the prepared g-CN molecular species, which is believed to be a dimeric tris-s-triazine, as well as attributed to insignificant solvent influence on the delocalized C=N vibrations. Vibrational transition density cubes were also computed for the proposed g-CN dimer, confirming the heterocyclic C=N stretching nature of the three IR absorption peaks. Intramolecular Vibrational Energy transfer dynamics and spectral diffusion of the g-CN system were characterized by examining a series of time-dependent 2D IR spectra. A picosecond intramolecular Vibrational Energy redistribution process was found to occur among these de...
Pengyun Yu - One of the best experts on this subject based on the ideXlab platform.
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ultrafast intermolecular Vibrational Energy transfer in hexahydro 1 3 5 trinitro 1 3 5 triazine in molecular crystal by 2d ir spectroscopy
The Journal of Physical Chemistry, 2020Co-Authors: Pengyun Yu, Juan Zhao, Jianping WangAbstract:Cyclic nitramine hexahydro-1,3,5-trinitro-s-triazine (HHTT) is an important energetic molecule with a variety of applications. In this work, structural dynamics and Vibrational-Energy transfer dynamics of HHTT were investigated using steady-state infrared (IR), femtosecond time-resolved IR, and two-dimensional (2D) IR spectroscopic methods. Two different structural forms of HHTT (isolated molecules dissolved in DMSO and microcrystal dispersed in paraffin oil) were examined using the NO₂ asymmetric stretching mode as a structural marker. Both intra- and intermolecular Vibrational Energy transfers were observed in HHTT microcrystal, where the well-known α-conformation was retained. However, less perfect α-HHTT species was found in DMSO. An intermolecular Energy dissipation pathway was found to be related to Davydov splitting in the microcrystal form of HHTT, which originates from intermolecular interactions (e.g., electrostatic and hydrogen bonds). Experimental results were supported by quantum-chemistry computations. In addition, both Vibrational excited-state relaxation and Vibrational Energy-transfer processes were found to be more efficient in HHTT microcrystal than in the solvated form. Our work provides a chemical-bond level of insight into the nitro group-containing energetic materials.
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ultrafast intramolecular Vibrational Energy transfer in carbon nitride hydrocolloid examined by femtosecond two dimensional infrared spectroscopy
Journal of Chemical Physics, 2019Co-Authors: Xuan Zheng, Pengyun Yu, Jianping WangAbstract:In this work, ultrafast Vibrational and structural processes in a graphitic carbon nitride hydrocolloid system were studied using a combination of linear infrared and nonlinear two-dimensional infrared (2D IR) spectroscopies. The experimentally observed three IR line shapes in the C=N stretching vibration frequency region were analyzed and attributed to the rigid and conjugated molecular frame of the prepared g-CN molecular species, which is believed to be a dimeric tris-s-triazine, as well as attributed to insignificant solvent influence on the delocalized C=N vibrations. Vibrational transition density cubes were also computed for the proposed g-CN dimer, confirming the heterocyclic C=N stretching nature of the three IR absorption peaks. Intramolecular Vibrational Energy transfer dynamics and spectral diffusion of the g-CN system were characterized by examining a series of time-dependent 2D IR spectra. A picosecond intramolecular Vibrational Energy redistribution process was found to occur among these delocalized C=N stretching modes, acting as an efficient Vibrational Energy transfer channel. This work reasonably connects the experimentally observed IR signature to a specific g-CN structure and also provides the first report on the ultrafast intramolecular processes of such carbon nitride systems. The obtained results are fundamentally important for understanding the molecular mechanisms of such carbon-nitride based functional materials.In this work, ultrafast Vibrational and structural processes in a graphitic carbon nitride hydrocolloid system were studied using a combination of linear infrared and nonlinear two-dimensional infrared (2D IR) spectroscopies. The experimentally observed three IR line shapes in the C=N stretching vibration frequency region were analyzed and attributed to the rigid and conjugated molecular frame of the prepared g-CN molecular species, which is believed to be a dimeric tris-s-triazine, as well as attributed to insignificant solvent influence on the delocalized C=N vibrations. Vibrational transition density cubes were also computed for the proposed g-CN dimer, confirming the heterocyclic C=N stretching nature of the three IR absorption peaks. Intramolecular Vibrational Energy transfer dynamics and spectral diffusion of the g-CN system were characterized by examining a series of time-dependent 2D IR spectra. A picosecond intramolecular Vibrational Energy redistribution process was found to occur among these de...
Dirk Schwarzer - One of the best experts on this subject based on the ideXlab platform.
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transporting and concentrating Vibrational Energy to promote isomerization
Nature, 2021Co-Authors: Alec M Wodtke, Dirk Schwarzer, Jascha A Lau, Li Chen, Arnab Choudhury, Varun B VermaAbstract:Visible-light absorption and transport of the resultant electronic excitations to a reaction centre through Forster resonance Energy transfer1-3 (FRET) are critical to the operation of biological light-harvesting systems4, and are used in various artificial systems made of synthetic dyes5, polymers6 or nanodots7,8. The fundamental equations describing FRET are similar to those describing vibration-to-vibration (V-V) Energy transfer9, and suggest that transport and localization of Vibrational Energy should, in principle, also be possible. Although it is known that Vibrational excitation can promote reactions10-16, transporting and concentrating Vibrational Energy has not yet been reported. We have recently demonstrated orientational isomerization enabled by Vibrational Energy pooling in a CO adsorbate layer on a NaCl(100) surface17. Here we build on that work to show that the isomerization reaction proceeds more efficiently with a thick 12C16O overlayer that absorbs more mid-infrared photons and transports the resultant Vibrational excitations by V-V Energy transfer to a 13C18O-NaCl interface. The Vibrational Energy density achieved at the interface is 30 times higher than that obtained with direct excitation of the interfacial CO. We anticipate that with careful system design, these concepts could be used to drive other chemical transformations, providing new approaches to condensed phase chemistry.
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nonequilibrium molecular dynamics simulations of Vibrational Energy relaxation of hod in d2o
Journal of Chemical Physics, 2009Co-Authors: Alexander Kandratsenka, Dirk Schwarzer, J Schroeder, V S VikhrenkoAbstract:Vibrational Energy relaxation of HOD in deuterated water is investigated performing classical nonequilibrium molecular dynamics simulations. A flexible SPC/E model is employed to describe the intermolecular interactions and the intramolecular potential of the D(2)O solvent. A more accurate intramolecular potential is used for HOD. Our results for the OH stretch, OD stretch, and HOD bend Vibrational relaxation times are 2.7, 0.9, and 0.57 ps, respectively. Exciting the OH stretching mode the main relaxation pathway involves a transition to the bending vibration. These results are in agreement with recent semiclassical Landau-Teller calculations. Contrary to this previous work, however, we observe a strong coupling of bending and OH stretching mode to the HOD rotation. As a result almost half of the total Vibrational Energy is transferred through the HOD rotation to the bath. At the same time the most efficient acceptor mode is the D(2)O rotation indicating the importance of resonant libration-to-libration Energy transfer. We also find significant Vibrational excitation of the D(2)O bending mode of the D(2)O solvent by V-V Energy transfer from the HOD bending mode.
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intramolecular Vibrational Energy redistribution in bridged azulene anthracene compounds ballistic Energy transport through molecular chains
Journal of Chemical Physics, 2004Co-Authors: Dirk Schwarzer, Peter Kutne, Christian Schroder, J TroeAbstract:Intramolecular Vibrational Energy flow in excited bridged azulene-anthracene compounds is investigated by time-resolved pump-probe laser spectroscopy. The bridges consist of molecular chains and are of the type (CH2)m with m up to 6 as well as (CH2OCH2)n (n=1,2) and CH2SCH2. After light absorption into the azulene S1 band and subsequent fast internal conversion, excited molecules are formed where the Vibrational Energy is localized at the azulene side. The Vibrational Energy transfer through the molecular bridge to the anthracene side and, finally, to the surrounding medium is followed by probing the red edge of the azulene S3 absorption band at 300 nm and/or the anthracene S1 absorption band at 400 nm. In order to separate the time scales for intramolecular and intermolecular Energy transfer, most of the experiments were performed in supercritical xenon where Vibrational Energy transfer to the bath is comparably slow. The intramolecular equilibration proceeds in two steps. About 15%–20% of the excitation...
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Real-Time Probing of Intramolecular Vibrational Energy Redistribution and Intermolecular Vibrational Energy Transfer of Selectively Excited CH2I2 Molecules in Solution †
Journal of Physical Chemistry A, 2001Co-Authors: A. Charvat, J. Assmann, Bernd Abel, Dirk SchwarzerAbstract:Competition between intramolecular Vibrational Energy redistribution (IVR) and intermolecular Vibrational Energy transfer (VET) of excited methylene iodide (CH2I2) in solution has been measured in real time. After excitation of the C−H− stretch overtone and C−H− stretch containing combination bands of CH2I2 between 1.7 and 2.4 μm an increase followed by a decrease in the transient electronic absorption at 400 nm has been monitored. The transient absorption has been attributed to Vibrational Energy flow from the initially excited degrees of freedom to Vibrational states with larger Franck-Condon (FC) factors for the electronic transition (long wavelength wing) and Energy loss due to Energy transfer to the solvent. A model based upon the dependence of the electronic absorption on the internal Energy 〈E〉 of CH2I2 has been used to determine the times for intramolecular Vibrational Energy redistribution and intermolecular Energy transfer to the solvent. In the simplest version of our model the internal Energy ...
Dana D Dlott - One of the best experts on this subject based on the ideXlab platform.
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controlling Vibrational Energy flow in liquid alkylbenzenes
Journal of Physical Chemistry B, 2013Co-Authors: Brandt C Pein, Dana D DlottAbstract:Ultrafast infrared (IR) Raman spectroscopy was used to study Vibrational Energy in ϕ–S alkylbenzenes, where ϕ = C6H5 and substituents S were CH3– (toluene), (CH3)2CH– (isopropylbenzene, IPB), or (CH3)3C– (t-butylbenzene, TBB). Using methods described previously,1 the normal modes were classified as phenyl (ϕ), substituent (S), or global (G). IR pulses were tuned to find conditions that maximized the localization of initial CH-stretch excitations on ϕ or S. Anti-Stokes Raman spectroscopy measured transient Energy content of Raman-active S, ϕ, and G modes, to determine the rates of phenyl to substituent (Φ → S) or substituent to phenyl (S → Φ) transfer during the first few picoseconds, when Energy transfer was mainly intramolecular. Since phenyl CH-stretches were 90–130 cm–1 uphill in Energy from substituent CH-stretches, of interest were S → Φ processes where molecular structure and local couplings were more important than Energy differences. The Φ → S process efficiencies were small and about equal with a...
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Vibrational Energy dynamics of glycine n methylacetamide and benzoate anion in aqueous d2o solution
Journal of Physical Chemistry A, 2009Co-Authors: Ying Fang, Shinsuke Shigeto, Nak Hyun Seong, Dana D DlottAbstract:Ultrafast infrared-Raman spectroscopy is used to study Vibrational Energy dynamics of three molecules in aqueous solution (D2O) that serve as models for the building blocks of peptides. These are glycine-d3 zwitterion (GLY), N-methylacetamide-d (NMA), and benzoate anion (BZ). GLY is the simplest amino acid, NMA a model compound with a peptide bond, and BZ a model for aromatic side chains. An ultrashort IR pulse pumps a parent CH-stretch on each solute. Anti-Stokes Raman monitors Energy flow through the solutes’ strongly Raman-active transitions. Stokes Raman of D2O stretching functions as a molecular thermometer to monitor Energy dissipation from solute to solvent. A three-stage model is used to summarize the Vibrational Energy redistribution process and to provide a framework for discussing Energy dynamics of different molecules. The initial CH-stretch excitation is found to be delocalized over some or all of the solute molecule in NMA and BZ but not in GLY. The overall time constants for Energy dissipat...
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Vibrational Energy transfer across a reverse micelle surfactant layer
Science, 2004Co-Authors: John Christopher Deak, Yoonsoo Pang, Timothy D Sechler, Zhaohui Wang, Dana D DlottAbstract:In a suspension of reverse micelles, in which the surfactant sodium dioctyl sulfosuccinate (AOT) separates a water nanodroplet from a bulk nonpolar CCl4 phase, ultrafast Vibrational spectroscopy was used to study Vibrational Energy transfer from the nanodroplet through the AOT interfacial monolayer to the surrounding CCl4. Most of the Vibrational Energy from the nanodroplet was transferred to the polar AOT head group within 1.8 picoseconds and then out to the CCl4 within 10 picoseconds. Vibrational Energy pumped directly into the AOT tail resulted in a slower 20- to 40-picosecond transfer of Energy to the CCl4.
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Vibrational Energy relaxation pathways of water
Chemical Physics Letters, 2003Co-Authors: Andrei V Pakoulev, Yoonsoo Pang, Zhaohui Wang, Dana D DlottAbstract:Abstract Vibrational Energy relaxation (VR) of the OH stretch ν OH and bend δ H 2 O in water is studied by the mid-IR pump with anti-Stokes Raman probe technique. The broad ν OH band in water consists of two inhomogeneously broadened subbands. VR in the larger red-shifted subband ν OH R , with T 1 =0.55 ps, is shown to occur by the mechanism ν OH → δ H 2 O (1/3) and ν OH → ground state (2/3). VR in the smaller longer-lived blue-shifted subband ν OH B , with T 1 =0.75 ps, occurs by the mechanism ν OH → ground state. The bending fundamental δ H 2 O decays directly to the ground state with T 1 =1.4 ps.
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watching Vibrational Energy transfer in liquids with atomic spatial resolution
Science, 2002Co-Authors: Zhaohui Wang, Andrei V Pakoulev, Dana D DlottAbstract:Ultrafast spectroscopy was used to study Vibrational Energy transfer between Vibrational reporter groups on different parts of a molecule in a liquid. When OH stretching vibrations of different alcohols were excited by mid-infrared laser pulses, Vibrational Energy was observed to move through intervening CH2 or CH groups, taking steps up and down in Energy, ending up at terminal CH3 groups. For each additional CH2 group in the path between OH and CH3, the time for Vibrational Energy transfer increased by about 0.4 picosecond.
Juan Zhao - One of the best experts on this subject based on the ideXlab platform.
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ultrafast intermolecular Vibrational Energy transfer in hexahydro 1 3 5 trinitro 1 3 5 triazine in molecular crystal by 2d ir spectroscopy
Journal of Physical Chemistry C, 2020Co-Authors: Lu Shi, Juan Zhao, Jianping WangAbstract:Cyclic nitramine hexahydro-1,3,5-trinitro-s-triazine (HHTT) is an important energetic molecule with a variety of applications. In this work, structural dynamics and Vibrational-Energy transfer dyna...
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ultrafast intermolecular Vibrational Energy transfer in hexahydro 1 3 5 trinitro 1 3 5 triazine in molecular crystal by 2d ir spectroscopy
The Journal of Physical Chemistry, 2020Co-Authors: Pengyun Yu, Juan Zhao, Jianping WangAbstract:Cyclic nitramine hexahydro-1,3,5-trinitro-s-triazine (HHTT) is an important energetic molecule with a variety of applications. In this work, structural dynamics and Vibrational-Energy transfer dynamics of HHTT were investigated using steady-state infrared (IR), femtosecond time-resolved IR, and two-dimensional (2D) IR spectroscopic methods. Two different structural forms of HHTT (isolated molecules dissolved in DMSO and microcrystal dispersed in paraffin oil) were examined using the NO₂ asymmetric stretching mode as a structural marker. Both intra- and intermolecular Vibrational Energy transfers were observed in HHTT microcrystal, where the well-known α-conformation was retained. However, less perfect α-HHTT species was found in DMSO. An intermolecular Energy dissipation pathway was found to be related to Davydov splitting in the microcrystal form of HHTT, which originates from intermolecular interactions (e.g., electrostatic and hydrogen bonds). Experimental results were supported by quantum-chemistry computations. In addition, both Vibrational excited-state relaxation and Vibrational Energy-transfer processes were found to be more efficient in HHTT microcrystal than in the solvated form. Our work provides a chemical-bond level of insight into the nitro group-containing energetic materials.
