Analogues of 2D photon echo methods in which two population times are sampled have recently been used to expose heterogeneity in chemical kinetics. In this work, the two population times sampled for a transition metal complex are transformed into a 2D rate spectrum using the maximum entropy method. The 2D rate spectrum suggests heterogeneity in the vibrational cooling (VC) rate within the ensemble. In addition, a cross peak associated with VC and back electron transfer (BET) dynamics reveals correlation between the two processes. We hypothesize that an increase in the strength of solute-solvent interactions, which accelerates VC, drives the system toward the activationless regime of BET.
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http://dx.doi.org/10.1063/1.4962670 | DOI Listing |
J Phys Chem A
January 2025
University of Göttingen, Institute for Physical Chemistry, Tammannstraße 6, 37077,Göttingen Germany.
Rotational spectroscopy is an excellent tool for structure determination, which can provide additional insights into local electronic structure by investigating the hyperfine pattern due to nuclear quadrupole coupling. Jet-cooled molecules are good experimental benchmark targets for electronic structure calculations, as they are free of environmental effects. We report the rotational spectra of 2-chlorobenzaldehyde, 3-chlorobenzaldehyde, and 4-chlorobenzaldehyde, including a complete experimental description of the nuclear quadrupole coupling constants, which were previously not experimentally determined.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
The cyano-cyclopentadiene molecule (CN-CH) has attracted significant interest since its detection in the interstellar medium, but the radical (CN-CH) and anionic (CN-CH) forms of cyano-cyclopentadiene have not been studied. The cyano-cyclopentadienyl radical (CN-Cp) has a strong dipole moment, rendering it an ideal system for vibrational and rotational spectroscopy. We report an investigation of the cryogenically cooled cyano-cyclopentadienide anion (CN-Cp) using high-resolution photoelectron imaging, photodetachment spectroscopy, and resonant photoelectron imaging.
View Article and Find Full Text PDFChirality
January 2025
JASCO Corporation, Japan.
A vibrational circular dichroism (VCD) instrument having a thermoelectrically cooled detector (denoted as a TEC unit) was constructed in this study. An electronic device, instead of liquid nitrogen, was employed in the instrument to cool the detector. The feasibility of the system was examined by recording the VCD spectra of liquid pinenes and insect wings.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
Various electronically excited states and the feasibility of direct laser cooling of SH, SeH, and TeH are investigated using the highly accurate ab initio and dynamical methods. For the detailed calculations of the seven low-lying Λ-S states of SH, we utilized the internally contracted multireference configuration interaction approach, considering the spin-orbit coupling (SOC) effects. Our calculated spectroscopic constants are in very good agreement with the available experimental results.
View Article and Find Full Text PDFACS Nano
January 2025
School of Information Science and Technology and Department of Optical Science and Engineering and Key Laboratory of Micro and Nano Photonic Structures (MOE), Fudan University, Shanghai 200433, China.
The formation of large polarons resulting from the Fröhlich coupling of photogenerated carriers with the polarized crystal lattice is considered crucial in shaping the outstanding optoelectronic properties in hybrid organic-inorganic perovskite crystals. Until now, the initial polaron dynamics after photoexcitation have remained elusive in the hybrid perovskite system. Here, based on the terahertz time-domain spectroscopy and optical-pump terahertz probe, we access the nature of interplay between photoexcited unbound charge carriers and optical phonons in MAPbBr within the initial 5 ps after excitation and have demonstrated the simultaneous existence of both electron- and hole-polarons, together with the photogenerated carrier dynamic process.
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