Recent experiments indicate that the NO stretch of 4-nitrobenzenethiol (NBT) attached to gold can be selectively excited via plasmonic excitation, catalyzing the decomposition of NBT. However, the effectiveness of catalysis is limited by intramolecular vibrational redistribution, which depletes the population of the excited NO stretch in a few picoseconds. In this study, vibrational lifetimes of the NO stretch are computed quantum mechanically for 20 substituted NBTs, including 10 chemical groups in the meta and ortho positions, attached to plasmonic nanoparticles. Variation in the lifetime of the NO stretch with chemical substitution arises from the tuning of resonances as well as systematic changes in values of anharmonic constants. The lifetime of the NO stretch of NBT depends largely on resonances involving three other modes. Upon substitution, one of those modes shifts far enough in frequency that it no longer affects the NO stretch lifetime. For substituents in the ortho position, new resonances appear that can shorten the lifetime, but most are detuned, and the coupling is weaker for the same substituents in the meta position. The impact of the longer NO stretch lifetimes found, particularly for substituents in the meta position, on enhancing the population of the NO stretch and catalysis is discussed.
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http://dx.doi.org/10.1021/acs.jpca.4c08207 | DOI Listing |
J Phys Chem B
March 2025
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
It has been shown that 4-cyanoindole-2'-deoxyribonucleoside (4CNI-NS) is a versatile spectroscopic probe of DNA structure and dynamics, as it can pair with all four natural DNA bases. However, its photophysics have not been examined in detail. Herein, we employed multiple techniques, including static fluorescence spectroscopy, time-resolved fluorescence spectroscopy, transient infrared spectroscopy, and theoretical calculations, to assess the photophysical properties of this nucleoside analogue in a series of solvents.
View Article and Find Full Text PDFJ Phys Chem Lett
March 2025
Institute of Quantum Physics, Hunan Key Laboratory of Nanophotonics and Devices, Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics, Central South University, Changsha 410083, China.
Defect-assisted ion migration is one of the important issues that results in instability and non-radiative losses in hybrid organic-inorganic metal halide perovskite solar cells. In this work, based on the deep potential (DP) model, a long-time-scale molecular dynamics (MD) simulation has been employed to capture the interstitial-assisted iodine migration process. The results indicate that, when interstitial iodine (I) begins to migrate, the serious structural distortion becomes mild, weakening the electron-vibration interaction.
View Article and Find Full Text PDFJ Am Chem Soc
March 2025
Department of Chemistry, University of Gour Banga, Malda 732103, India.
Charge separation is at the heart of solar energy applications, and efficient materials require fast photoinduced electron transfer (ET) and slow charge recombination (CR). Using time-dependent self-consistent charge density functional tight-binding theory combined with nonadiabatic (NA) molecular dynamics, we report a detailed analysis of ET and CR in hybrids composed of photoactive covalent organic polyhedra (COP) and encapsulated fullerenes. The ET occurs on a subpicosecond time scale and accelerates with increasing fullerene diameter, C to C to C.
View Article and Find Full Text PDFJ Phys Chem B
February 2025
Department of Chemistry, Stanford University, Stanford, California 94305, United States.
Health and environmental risks posed by volatile organic solvents create an incentive to develop safer, less volatile solvents with the appropriate functionality. Deep eutectic solvents and other low-volatility organic mixtures offer a highly tunable alternative through a mixture composition selection. However, a significant gap exists in understanding the relationship between molecular-level properties and the resulting solvation and transport properties.
View Article and Find Full Text PDFRev Sci Instrum
February 2025
Graduate School of China Academy of Engineering Physics, Beijing 100193, China.
Dynamics of materials under high-pressure conditions has been an important focus of materials science, especially in the timescale of pico- and femto-second electronic and vibrational motion, which is typically probed by ultrafast laser pulses. To probe such dynamics, it requires an integration of high-pressure devices with the ultrafast laser system. The combination of transient absorption (TA) spectroscopy with diamond anvil cells (DACs) is a novel solution, yet the intense pump scattering light resulting from the small cross section of the DAC may limit the spectral range of the detected signal.
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