Exploring how charge-changing affects the photoluminescence of small organic dyes presents challenges. Here, helium tagging photodissociation (PD) action spectroscopy in the gas phase and dispersed laser-induced fluorescence (DF) spectroscopy in the solid Ne matrix are used to compare the intrinsic photophysical properties of pyronin Y cation [PY] and its one electron-reduced neutral radical [PY] at 5 K. Whereas the cation shows efficient visible photoluminescence, no emission from the neutral, in line with theoretical predictions, was detected. B3LYP/aug-cc-pVDZ calculations based on the TD-DFT/FCHT method allow for unambiguous assignment of recorded vibrationally resolved absorption and emission spectra. Surprisingly, our experimental sensitivity was high enough to also observe electronic preresonance Raman (ePR-Raman) spectra of [PY], with a significant efficiency factor (EF). These characteristics of the [PY]/[PY] pair suggest that appropriately functionalized derivatives may open new perspectives in the area of in vivo bioimagining microscopy and find applications in various sophisticated stimulated-Raman spectroscopies.
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http://dx.doi.org/10.1021/acs.jpclett.3c02651 | DOI Listing |
J Phys Chem A
January 2025
Department of Physics, Yantai University, Yantai 264005, China.
Vibronic coupling and multiple electronic states effect play a pivotal role in the molecular spectroscopy of large systems. Herein, we present a detailed theoretical study on the absorption (ABS) and electronic circular dichroism (ECD) spectra of three [7]helicene derivatives in chloroform, with a particular emphasis on the significance of vibronic coupling and the multiple electronic states effect in spectral simulations. The vertical gradient (VG) and vertical Hessian (VH) models, incorporating the Franck-Condon (FC) effect and Herzberg-Teller (HT) contribution, are considered in the vibronic calculations.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Huygens-Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
Fluorescence spectra of single terrylene molecules adsorbed on hexagonal boron nitride flakes were recorded at cryogenic temperatures. The pure electronic transitions of terrylene molecules are spread over a broad energy scale from 570 to 610 nm. Surprisingly, peaks in the vibrationally resolved fluorescence spectrum show intensity variations of ≤20-fold between molecules.
View Article and Find Full Text PDFJ Phys Chem A
December 2024
School of Geographical Sciences, Shanxi Normal University, No. 339, Taiyu Road, Taiyuan, Shanxi 030031, People's Republic of China.
The conjugate-pair molecules of CO and CPt provide a prototype of the autogenic isolobal relationship between the O and Pt atoms that can rationalize the structure and reactivity trends of platinum carbides. Herein, the photoelectron detachment at 532 nm has been recorded for the gas-phase CPt by using the photoelectron velocity-map imaging spectroscopy. The vibrationally resolved ground-state transition reveals a wealth of information concerning the electronic ground states of CPt.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, 28006 Madrid, Spain.
A detailed analysis of the low collision energy (0.03-10 meV) integral reaction cross-section has been carried out for the F + HD ( = 0, 1; = 1)→ HF(DF) + D(H) reaction using accurate, fully converged time-independent hyperspherical quantum dynamics. Particular attention has been paid to the shape (orbiting) resonances and their assignment to the orbital () and total () angular momenta as well as to the product's state resolved cross-sections at the energies of the resonances.
View Article and Find Full Text PDFACS Phys Chem Au
November 2024
Department of Chemistry, University of Sheffield. Sheffield S3 7HF, U.K.
Donor-bridge-acceptor complexes (D-B-A) are important model systems for understanding of light-induced processes. Here, we apply two-color two-dimensional infrared (2D-IR) spectroscopy to D-B-A complexes with a -Pt(II) acetylide bridge (D-C≡C-Pt-C≡C-A) to uncover the mechanism of vibrational energy redistribution (IVR). Site-selective C isotopic labeling of the bridge is used to decouple the acetylide modes positioned on either side of the Pt-center.
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