Pub Date : 2025-01-30DOI: 10.1021/acs.jpclett.4c02984
Gwendylan A. Turner, Caitlin E. Dunlap, Alexander J. Higgins, Garth J. Simpson
Dark-field and confocal approaches to circular dichroism (CD) spectroscopy of uniaxial thin films examine the relationship between symmetry and incoherence in the nonreciprocal CD response, or the component that is antisymmetric about the light propagation direction. Modifying a conventional CD spectrometer for low-angle scattering detection isolates incoherent contributions to nonreciprocal CD of drop-cast thin films, boasting 5-to-10-fold enhancements in CD dissymmetry parameters. Conversely, confocal detection suppresses the nonreciprocal CD response. These collective measurements provide the first compelling evidence of early predictions by Hecht and Barron, which indicate large chiral- and interface-specific CD observables from scattered signals in uniaxially oriented assemblies. According to this theory, nonreciprocal CD is possible within the electric dipole approximation, leading to chiral-specific observables exceeding reciprocal, isotropic contributions. Dark-field absorbance CD (DCD) spectroscopy thus offers new insights into molecular and macromolecular arrangements with interface selectivity and chiral specificity.
{"title":"Dark-Field Absorbance Circular Dichroism of Oriented Chiral Thin Films","authors":"Gwendylan A. Turner, Caitlin E. Dunlap, Alexander J. Higgins, Garth J. Simpson","doi":"10.1021/acs.jpclett.4c02984","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02984","url":null,"abstract":"Dark-field and confocal approaches to circular dichroism (CD) spectroscopy of uniaxial thin films examine the relationship between symmetry and incoherence in the nonreciprocal CD response, or the component that is antisymmetric about the light propagation direction. Modifying a conventional CD spectrometer for low-angle scattering detection isolates incoherent contributions to nonreciprocal CD of drop-cast thin films, boasting 5-to-10-fold enhancements in CD dissymmetry parameters. Conversely, confocal detection suppresses the nonreciprocal CD response. These collective measurements provide the first compelling evidence of early predictions by Hecht and Barron, which indicate large chiral- and interface-specific CD observables from scattered signals in uniaxially oriented assemblies. According to this theory, nonreciprocal CD is possible within the electric dipole approximation, leading to chiral-specific observables exceeding reciprocal, isotropic contributions. Dark-field absorbance CD (DCD) spectroscopy thus offers new insights into molecular and macromolecular arrangements with interface selectivity and chiral specificity.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"39 4 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143056857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1021/acs.jpclett.4c03111
P. Śledzik, P.M. Biesheuvel, Q. Shu, H.V.M. Hamelers, S. Porada
We investigate a continuous electrochemical pH-swing method to capture CO2 from a gas phase. The electrochemical cell consists of a single cation-exchange membrane (CEM) and a recirculation of a mixture of salt and phenazine-based redox-active molecules. In the absorption compartment, this solution is saturated by CO2 from a mixed gas phase at high pH. In the electrochemical cell, pH is reduced, and CO2 is selectively released in a desorption step. We investigate the influence of redox molecule concentration on the charge storage capacity of the solution, as well as the impact of current density and solution recirculation rate on process performance. A theoretical framework, based on a minimal set of assumptions, is established. This framework describes the data very accurately and can be used for system design and optimization. We evaluate the trade-off between energy consumption and CO2 capture rate and compare with published reports. We report a low energy consumption of 32 kJ/mol of CO2 at a capture rate of 39 mmol/m2/min.
{"title":"Continuous Electrochemical Carbon Capture via Redox-Mediated pH Swing─Experimental Performance and Process Modeling","authors":"P. Śledzik, P.M. Biesheuvel, Q. Shu, H.V.M. Hamelers, S. Porada","doi":"10.1021/acs.jpclett.4c03111","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03111","url":null,"abstract":"We investigate a continuous electrochemical pH-swing method to capture CO<sub>2</sub> from a gas phase. The electrochemical cell consists of a single cation-exchange membrane (CEM) and a recirculation of a mixture of salt and phenazine-based redox-active molecules. In the absorption compartment, this solution is saturated by CO<sub>2</sub> from a mixed gas phase at high pH. In the electrochemical cell, pH is reduced, and CO<sub>2</sub> is selectively released in a desorption step. We investigate the influence of redox molecule concentration on the charge storage capacity of the solution, as well as the impact of current density and solution recirculation rate on process performance. A theoretical framework, based on a minimal set of assumptions, is established. This framework describes the data very accurately and can be used for system design and optimization. We evaluate the trade-off between energy consumption and CO<sub>2</sub> capture rate and compare with published reports. We report a low energy consumption of 32 kJ/mol of CO<sub>2</sub> at a capture rate of 39 mmol/m<sup>2</sup>/min.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"24 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1021/acs.jpclett.4c03198
Lillian I. Payne Torres, Anna O. Schouten, LeeAnn M. Sager-Smith, David A. Mazziotti
Exciton condensation, the Bose–Einstein-like condensation of quasibosonic particle-hole pairs, has been the subject of much theoretical and experimental interest and holds promise for ultraenergy-efficient technologies. Recent advances in bilayer systems, such as transition metal dichalcogenide heterostructures, have brought us closer to the experimental realization of exciton condensation without the need for high magnetic fields. In this perspective, we explore progress toward understanding and realizing exciton condensation, with a particular focus on the characteristic theoretical signature of exciton condensation: an eigenvalue greater than one in the particle-hole reduced density matrix, which signifies off-diagonal long-range order. This metric bridges the gap between theoretical predictions and experimental realizations by providing a unifying framework that connects exciton condensation to related phenomena, such as Bose–Einstein condensation and superconductivity. Furthermore, our molecular approach integrates exciton condensation with broader excitonic phenomena, including exciton-related entanglement and correlation, unlocking potential advancements in fields like quantum materials and energy transport. We discuss connections between recent experimental and theoretical work and highlight the discoveries that may arise from approaching exciton condensation from a molecular perspective.
{"title":"A Molecular Perspective of Exciton Condensation from Particle-Hole Reduced Density Matrices","authors":"Lillian I. Payne Torres, Anna O. Schouten, LeeAnn M. Sager-Smith, David A. Mazziotti","doi":"10.1021/acs.jpclett.4c03198","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03198","url":null,"abstract":"Exciton condensation, the Bose–Einstein-like condensation of quasibosonic particle-hole pairs, has been the subject of much theoretical and experimental interest and holds promise for ultraenergy-efficient technologies. Recent advances in bilayer systems, such as transition metal dichalcogenide heterostructures, have brought us closer to the experimental realization of exciton condensation without the need for high magnetic fields. In this perspective, we explore progress toward understanding and realizing exciton condensation, with a particular focus on the characteristic theoretical signature of exciton condensation: an eigenvalue greater than one in the particle-hole reduced density matrix, which signifies off-diagonal long-range order. This metric bridges the gap between theoretical predictions and experimental realizations by providing a unifying framework that connects exciton condensation to related phenomena, such as Bose–Einstein condensation and superconductivity. Furthermore, our molecular approach integrates exciton condensation with broader excitonic phenomena, including exciton-related entanglement and correlation, unlocking potential advancements in fields like quantum materials and energy transport. We discuss connections between recent experimental and theoretical work and highlight the discoveries that may arise from approaching exciton condensation from a molecular perspective.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"21 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1021/acs.jpclett.4c03119
Aditi Kumar, Rohan J. Hudson, Nikita A. Shumilov, Chao-Yang Lin, Trevor A. Smith, Nathaniel J. L. K. Davis, Eric C. Le Ru, Michael B. Price, Paul A. Hume, Justin M. Hodgkiss
The organic semiconductor Y6 has been extensively used as an acceptor in organic photovoltaic devices, yielding high efficiencies. Its unique properties include a high refractive index, intrinsic exciton dissociation, and barrierless charge generation in bulk heterojunctions. However, the direct impact of the crystal packing morphology on the photophysics of Y6 has remained elusive, hindering further development of heterojunction and homojunction devices. Herein, we study the photogenerated species in multiple distinct Y6 crystal packing geometries via transient absorption spectroscopy and photovoltaic measurements of the corresponding single-component devices. Our results reveal that “co-facial” interactions drive the generation of charge-transfer states in neat films of Y6 and that exciton dissociation can be switched on and off by controlling these interactions. Additionally, we find that a combination of long-range order and more co-facial packing interactions accelerates the charge-transfer generation process and increases the exciton to charge-transfer conversion efficiency. These insights provide valuable structure–property relationships for optimizing device performance.
{"title":"Morphological Control of Y6 Thin Films Reveals Charge Transfer Is Facilitated by Co-facial Interactions","authors":"Aditi Kumar, Rohan J. Hudson, Nikita A. Shumilov, Chao-Yang Lin, Trevor A. Smith, Nathaniel J. L. K. Davis, Eric C. Le Ru, Michael B. Price, Paul A. Hume, Justin M. Hodgkiss","doi":"10.1021/acs.jpclett.4c03119","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03119","url":null,"abstract":"The organic semiconductor Y6 has been extensively used as an acceptor in organic photovoltaic devices, yielding high efficiencies. Its unique properties include a high refractive index, intrinsic exciton dissociation, and barrierless charge generation in bulk heterojunctions. However, the direct impact of the crystal packing morphology on the photophysics of Y6 has remained elusive, hindering further development of heterojunction and homojunction devices. Herein, we study the photogenerated species in multiple distinct Y6 crystal packing geometries via transient absorption spectroscopy and photovoltaic measurements of the corresponding single-component devices. Our results reveal that “co-facial” interactions drive the generation of charge-transfer states in neat films of Y6 and that exciton dissociation can be switched on and off by controlling these interactions. Additionally, we find that a combination of long-range order and more co-facial packing interactions accelerates the charge-transfer generation process and increases the exciton to charge-transfer conversion efficiency. These insights provide valuable structure–property relationships for optimizing device performance.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"40 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1021/acs.jpclett.4c02955
Gregory D. Scholes, Alexandra Olaya-Castro, Shaul Mukamel, Adam Kirrander, Kang-Kuen Ni, Gordon J. Hedley, Natia L. Frank
We discuss the goals and the need for quantum information science (QIS) in chemistry. It is important to identify concretely how QIS matters to chemistry, and we articulate some of the most pressing and interesting research questions at the interface between chemistry and QIS, that is, “chemistry-centric” research questions relevant to QIS. We propose in what ways and in what new directions the field should innovate, in particular where a chemical perspective is essential. Examples of recent research in chemistry that inspire scrutiny from a QIS perspective are provided, and we conclude with a wish list of open research problems.
{"title":"The Quantum Information Science Challenge for Chemistry","authors":"Gregory D. Scholes, Alexandra Olaya-Castro, Shaul Mukamel, Adam Kirrander, Kang-Kuen Ni, Gordon J. Hedley, Natia L. Frank","doi":"10.1021/acs.jpclett.4c02955","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02955","url":null,"abstract":"We discuss the goals and the need for quantum information science (QIS) in chemistry. It is important to identify concretely how QIS matters to chemistry, and we articulate some of the most pressing and interesting research questions at the interface between chemistry and QIS, that is, “chemistry-centric” research questions relevant to QIS. We propose in what ways and in what new directions the field should innovate, in particular where a chemical perspective is essential. Examples of recent research in chemistry that inspire scrutiny from a QIS perspective are provided, and we conclude with a wish list of open research problems.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"27 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1021/acs.jpclett.4c02951
John A. Tomko, Kiumars Aryana, Yifan Wu, Guoqing Zhou, Qiyan Zhang, Pat Wongwiset, Virginia Wheeler, Oleg V. Prezhdo, Patrick E. Hopkins
Vanadium oxide (VO2) is an exotic phase-change material with diverse applications ranging from thermochromic smart windows to thermal sensors, neuromorphic computing, and tunable metasurfaces. Nonetheless, the mechanism responsible for its metal–insulator phase transition remains a subject of vigorous debate. Here, we investigate the ultrafast dynamics of the photoinduced phase transition in VO2 under low perturbation conditions. By experimentally examining carrier relaxation dynamics at energy levels near the VO2 band gap (0.6–0.92 eV), we note that numerous optical features do not correspond to the first-order phase transition. Previous studies indeed induced such a phase transition, but they relied on fluences at least an order of magnitude higher, leading to temperature increases well above the transition threshold (340 K). Instead, for excitation fluences that correspond to lattice temperatures only in slight excess of the phase transition (absolute temperatures < 500 K), we find that the marked changes in optical properties are dominated by a shift in the electronic density of states/Fermi level. We find that this effect is a lattice-driven process and does not occur until sufficient energy has been transferred from the excited electrons into the phonon subsystem.
{"title":"Ultrafast Charge Carrier Dynamics in Vanadium Dioxide, VO2: Nonequilibrium Contributions to the Photoinduced Phase Transitions","authors":"John A. Tomko, Kiumars Aryana, Yifan Wu, Guoqing Zhou, Qiyan Zhang, Pat Wongwiset, Virginia Wheeler, Oleg V. Prezhdo, Patrick E. Hopkins","doi":"10.1021/acs.jpclett.4c02951","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02951","url":null,"abstract":"Vanadium oxide (VO<sub>2</sub>) is an exotic phase-change material with diverse applications ranging from thermochromic smart windows to thermal sensors, neuromorphic computing, and tunable metasurfaces. Nonetheless, the mechanism responsible for its metal–insulator phase transition remains a subject of vigorous debate. Here, we investigate the ultrafast dynamics of the photoinduced phase transition in VO<sub>2</sub> under low perturbation conditions. By experimentally examining carrier relaxation dynamics at energy levels near the VO<sub>2</sub> band gap (0.6–0.92 eV), we note that numerous optical features do not correspond to the first-order phase transition. Previous studies indeed induced such a phase transition, but they relied on fluences at least an order of magnitude higher, leading to temperature increases well above the transition threshold (340 K). Instead, for excitation fluences that correspond to lattice temperatures only in slight excess of the phase transition (absolute temperatures < 500 K), we find that the marked changes in optical properties are dominated by a shift in the electronic density of states/Fermi level. We find that this effect is a lattice-driven process and does not occur until sufficient energy has been transferred from the excited electrons into the phonon subsystem.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"47 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1021/acs.jpclett.4c03518
Longyue Yu, Xionghui Huang, Ning Feng, Wenwen Fu, Xia Xin, Jingcheng Hao, Hongguang Li
Multi-step Förster resonance energy transfer (FRET) plays a vital role in photosynthesis. While the energy transfer efficiency (ΦET) of a naturally occurring system can reach 95%, that of most artificial light-harvesting systems (ALHSs) is still limited. Herein, we propose a strategy to construct highly efficient ALHSs using a blue-emitting, supercooled ionic compound of naphthalimide (NPI) as the donor, a green-emitting BODIPY derivate as a relay acceptor, and a commercially available, red-emitting dye [rhodamine B (RhB)] as the final acceptor. The broad emission of the fluid donor can overlap simultaneously with the absorption of BODIPY and RhB, enabling the occurrence of a sequential FRET from NPI to BODIPY to RhB as well as a parallel FRET directly from NPI to RhB. These two complementary energy transfer routes lead to an overall ΦET up to 97.4%, which is the champion among all of the reported ALHSs and is also higher than that found in plants and photosynthetic bacteria. This strategy is universal, and ΦET of the system could be further improved by optimizing the structures of the fluid donor and relay acceptor.
{"title":"Solvent-Free Artificial Light-Harvesting System in a Fluid Donor with Highly Efficient Förster Resonance Energy Transfer","authors":"Longyue Yu, Xionghui Huang, Ning Feng, Wenwen Fu, Xia Xin, Jingcheng Hao, Hongguang Li","doi":"10.1021/acs.jpclett.4c03518","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03518","url":null,"abstract":"Multi-step Förster resonance energy transfer (FRET) plays a vital role in photosynthesis. While the energy transfer efficiency (Φ<sub>ET</sub>) of a naturally occurring system can reach 95%, that of most artificial light-harvesting systems (ALHSs) is still limited. Herein, we propose a strategy to construct highly efficient ALHSs using a blue-emitting, supercooled ionic compound of naphthalimide (NPI) as the donor, a green-emitting BODIPY derivate as a relay acceptor, and a commercially available, red-emitting dye [rhodamine B (RhB)] as the final acceptor. The broad emission of the fluid donor can overlap simultaneously with the absorption of BODIPY and RhB, enabling the occurrence of a sequential FRET from NPI to BODIPY to RhB as well as a parallel FRET directly from NPI to RhB. These two complementary energy transfer routes lead to an overall Φ<sub>ET</sub> up to 97.4%, which is the champion among all of the reported ALHSs and is also higher than that found in plants and photosynthetic bacteria. This strategy is universal, and Φ<sub>ET</sub> of the system could be further improved by optimizing the structures of the fluid donor and relay acceptor.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"117 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1021/acs.jpclett.4c03483
Xiaolong Li, Wenbin Fan, Xin Shao, Wei Fang, Dong H. Zhang, Mingfei Zhou, Joseph S. Francisco, Xiaoqing Zeng
The photochemistry of nitrous acid (HONO) plays a crucial role in atmospheric chemistry as it serves as a key source of hydroxyl radicals (OH) in the atmosphere; however, our comprehension of the underlying mechanism for the photochemistry of HONO especially in the presence of water is far from being complete as the transient intermediates in the photoreactions have not been observed. Herein, we report the photochemistry of microsolvated HONO by water in a cryogenic N2 matrix. Specifically, the 1:1 hydrogen-bonded water complex of HONO was facially prepared in the matrix through stepwise photolytic O2 oxidation of the water complex of imidogen (NH–H2O) via the intermediacy of the elusive water complex of peroxyl isomer HNOO. Upon photolysis at 193 nm, the matrix-isolated HONO–H2O complex decomposes by yielding the ternary water complex of OH and NO due to the matrix cage effect. The identification of this rare water-separated radical pair (OH–H2O–NO) with matrix-isolation infrared and ultraviolet–visible spectroscopy is aided by D, 15N, and 18O isotope labeling and quantum chemical calculations at the (U)CCSD/AVTZ level of theory, and its most stable structure exhibits separate hydrogen bonding interactions of the OH and NO radicals with H2O via OH···OH2 and ON···HOH contacts, respectively. This ternary complex is extremely unstable, as it undergoes spontaneous radical recombination to reform the HONO–H2O complex in the temperature range of 4–12 K through quantum-mechanical tunneling with 16/18O, H/D, 14/15N kinetic isotopic effects of 1.43, 2.33, and 0.91, respectively. At increased temperatures from 15 to 21 K, the recombination proceeds predominantly by overcoming the activation barrier with an estimated height of 0.12(1) kcal/mol.
{"title":"Photochemistry of Microsolvated Nitrous Acid: Observation of the Water-Separated Complex of Nitric Oxide and Hydroxyl Radical","authors":"Xiaolong Li, Wenbin Fan, Xin Shao, Wei Fang, Dong H. Zhang, Mingfei Zhou, Joseph S. Francisco, Xiaoqing Zeng","doi":"10.1021/acs.jpclett.4c03483","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03483","url":null,"abstract":"The photochemistry of nitrous acid (HONO) plays a crucial role in atmospheric chemistry as it serves as a key source of hydroxyl radicals (OH) in the atmosphere; however, our comprehension of the underlying mechanism for the photochemistry of HONO especially in the presence of water is far from being complete as the transient intermediates in the photoreactions have not been observed. Herein, we report the photochemistry of microsolvated HONO by water in a cryogenic N<sub>2</sub> matrix. Specifically, the 1:1 hydrogen-bonded water complex of HONO was facially prepared in the matrix through stepwise photolytic O<sub>2</sub> oxidation of the water complex of imidogen (NH–H<sub>2</sub>O) via the intermediacy of the elusive water complex of peroxyl isomer HNOO. Upon photolysis at 193 nm, the matrix-isolated HONO–H<sub>2</sub>O complex decomposes by yielding the ternary water complex of OH and NO due to the matrix cage effect. The identification of this rare water-separated radical pair (OH–H<sub>2</sub>O–NO) with matrix-isolation infrared and ultraviolet–visible spectroscopy is aided by D, <sup>15</sup>N, and <sup>18</sup>O isotope labeling and quantum chemical calculations at the (U)CCSD/AVTZ level of theory, and its most stable structure exhibits separate hydrogen bonding interactions of the OH and NO radicals with H<sub>2</sub>O via OH···OH<sub>2</sub> and ON···HOH contacts, respectively. This ternary complex is extremely unstable, as it undergoes spontaneous radical recombination to reform the HONO–H<sub>2</sub>O complex in the temperature range of 4–12 K through quantum-mechanical tunneling with <sup>16/18</sup>O, H/D, <sup>14/15</sup>N kinetic isotopic effects of 1.43, 2.33, and 0.91, respectively. At increased temperatures from 15 to 21 K, the recombination proceeds predominantly by overcoming the activation barrier with an estimated height of 0.12(1) kcal/mol.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"6 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Round-trip energy transfer (RTET) in the popular Er3+/Yb3+ upconversion (UC) system is a newly discovered mechanism for the red emission of Er3+ through Yb3+ as an intermediate ion. However, the importance of the RTET still remains a question. Here, we show in cubic Y2O3 that the new mechanism defeats conventional ones and dominates the red emission in both UC and down-shifting (DS) luminescence for a wide concentration range of Yb3+. The RTET enables the red UC emission to exhibit a similar time evolution as the green UC emission for Yb3+ concentration ≤10%, and its contribution to the red DS emission exceeds 90% for Yb3+ concentration ≥10%. As a unique feature, the temporal profile of the entire RTET process is presented for the first time. Our findings provide new physical insight into the regulation of color and temporal behavior of UC luminescence in the Yb3+/Er3+ system.
{"title":"The Important Round-Trip Energy Transfer for Excitation of the Red Emission in the Er3+/Yb3+ System","authors":"Yuchao Shi, Hao Wu, Huajun Wu, Liangliang Zhang, Guo-hui Pan, Yongshi Luo, Zhendong Hao, Jiahua Zhang","doi":"10.1021/acs.jpclett.4c03611","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03611","url":null,"abstract":"Round-trip energy transfer (RTET) in the popular Er<sup>3+</sup>/Yb<sup>3+</sup> upconversion (UC) system is a newly discovered mechanism for the red emission of Er<sup>3+</sup> through Yb<sup>3+</sup> as an intermediate ion. However, the importance of the RTET still remains a question. Here, we show in cubic Y<sub>2</sub>O<sub>3</sub> that the new mechanism defeats conventional ones and dominates the red emission in both UC and down-shifting (DS) luminescence for a wide concentration range of Yb<sup>3+</sup>. The RTET enables the red UC emission to exhibit a similar time evolution as the green UC emission for Yb<sup>3+</sup> concentration ≤10%, and its contribution to the red DS emission exceeds 90% for Yb<sup>3+</sup> concentration ≥10%. As a unique feature, the temporal profile of the entire RTET process is presented for the first time. Our findings provide new physical insight into the regulation of color and temporal behavior of UC luminescence in the Yb<sup>3+</sup>/Er<sup>3+</sup> system.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"36 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Glycolipids are known to stabilize biomembrane multilayers through preferential sugar–sugar interactions that act as weak transient membrane cross-links. Here, we use small-angle and quasi-elastic neutron scattering on oligolamellar phospholipid vesicles containing defined glycolipid fractions in order to elucidate the influence of glycolipids on membrane mechanics and dynamics. Small-angle neutron scattering (SANS) reveals that the oligolamellar vesicles (OLVs) obtained by extrusion are polydisperse with regard to the number of lamellae, n, which renders the interpretation of the quasi-elastic neutron spin echo (NSE) data nontrivial. To overcome this problem, we propose a method to model the NSE data in a rigorous fashion based on the obtained histograms of n and on their q-dependent intensity-weighted contribution. This procedure yields meaningful values for the bending rigidity of individual lipid membranes and insights into the mechanical coupling between adjacent membrane lamellae including the effect of the glycolipids.
{"title":"Small-Angle and Quasi-Elastic Neutron Scattering from Polydisperse Oligolamellar Vesicles Containing Glycolipids","authors":"Lukas Bange, Amin Rahimzadeh, Tetiana Mukhina, Regine von Klitzing, Ingo Hoffmann, Emanuel Schneck","doi":"10.1021/acs.jpclett.4c03454","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03454","url":null,"abstract":"Glycolipids are known to stabilize biomembrane multilayers through preferential sugar–sugar interactions that act as weak transient membrane cross-links. Here, we use small-angle and quasi-elastic neutron scattering on oligolamellar phospholipid vesicles containing defined glycolipid fractions in order to elucidate the influence of glycolipids on membrane mechanics and dynamics. Small-angle neutron scattering (SANS) reveals that the oligolamellar vesicles (OLVs) obtained by extrusion are polydisperse with regard to the number of lamellae, <i>n</i>, which renders the interpretation of the quasi-elastic neutron spin echo (NSE) data nontrivial. To overcome this problem, we propose a method to model the NSE data in a rigorous fashion based on the obtained histograms of <i>n</i> and on their <i>q</i>-dependent intensity-weighted contribution. This procedure yields meaningful values for the bending rigidity of individual lipid membranes and insights into the mechanical coupling between adjacent membrane lamellae including the effect of the glycolipids.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"39 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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