The ultrafast photo-induced dynamics of wild-type photoactive yellow protein and its site-directed mutant of E46Q in aqueous solution was studied at room temperature by femtosecond fluorescence spectroscopy using the optical Kerr-gate method. The vibronic structure appears, depending on the excitation photon energy, in the time-resolved fluorescence spectra just after photoexcitation, which winds with time and disappears on a time scale of sub-picoseconds. This result indicates that the wavepacket is localized in the electronic excited state followed by dumped oscillations and broadening, and also that the initial condition of the wavepacket prepared depending on the excitation photon energy affects much the following ultrafast dynamics in the electronic excited state.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1111/j.1751-1097.2008.00329.x | DOI Listing |
J Chem Phys
January 2025
Ideal Vacuum Products, LLC, 5910 Midway Park Blvd. NE, Albuquerque, New Mexico 87109, USA.
The hydroxysilylene (HSiOH) molecule has been spectroscopically identified in the gas phase for the first time. This highly reactive species was produced in a twin electric discharge jet using separate precursor streams of 16O2/18O2 and Si2H6/Si2D6, both diluted in high pressure argon. The strongest and most stable laser induced fluorescence (LIF) signals were obtained by applying an electric discharge to each of the precursor streams and then merging the discharge products just prior to expansion into vacuum.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of physical science and technology, ShanghaiTech University, Shanghai 201210, China.
Implanting heteroatoms into organic π-conjugated molecules (OCMS) offered a great opportunity to fine-tune the chemical structures and optoelectronic properties. This work describes a new family of 1,4-azaphosphinines with extended σ-π hyperconjugations. The photophysical studies revealed that azaphosphinines exhibited narrow-band thermally activated delayed fluorescence (TADF) ( full width at half-maximum: 26-40 nm).
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Istituto di Biostrutture e Bioimmagini-CNR (IBB-CNR), Via De Amicis 95, I-80145 Napoli, Italy.
We here simulate in the gas phase the population dynamics of guanine/cytosine (GC) and cytosine/guanine (CG) stacked dimers in B-DNA and A-DNA arrangement, following excitation in the lowest-energy band, and considering the four lowest-energy ππ* bright excited states, the three lowest-energy π* states, and the G → C charge-transfer (CT) state. We resort to a generalized Linear Vibronic Coupling (LVC) model parametrized with time-dependent density functional theory (TD-DFT) computations, exploiting a fragment-based diabatization and we run nonadiabatic quantum dynamical simulations with the multilayer version of the Multiconfigurational Time-Dependent Hartree (ML-MCTDH) approach. G → C CT results in a major decay process for GC in B-DNA but less in A-DNA arrangement, where also the population transfer to the lowest-energy excited state localized on C is an important intermonomer process.
View Article and Find Full Text PDFJ 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 PDFChem Sci
January 2025
Department of Chemistry, Rice University Houston Texas 77005 USA
We recently demonstrated molecular plasmons in cyanine dyes for the conversion of photon energy into mechanical energy through a whole-molecule coherent vibronic-driven-action. Here we present a model, a molecular plasmon analogue of molecular orbital theory and of plasmon hybridization in metal nanostructures. This model describes that molecular plasmons can be obtained from the combination or hybridization of elementary molecular fragments, resulting in molecules with hybridized plasmon resonances in the electromagnetic spectrum.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!