We obtained the electronic spectra of various methylated xanthine compounds including caffeine in a supersonic jet by resonant two-photon ionization spectroscopy. The methyl group in the tested methylated xanthine compounds has a distinct, site-dependent effect on the electronic spectrum. Methylation at the N3 position causes a significant red shift of the ππ* state, whereas methylation at the ...

This paper is devoted to the development and application of an effective computational approach for the prediction of band broadening in the electronic spectra of semi-flexible organic molecules in solution. The protocol is based on DFT, TD-DFT, and PCM computational techniques and attempts to take into account the three main contributions tuning electronic spectra, namely vibronic transitions,...

The particle-in-a-box model was used to analyze the conjugated bonds and π electrons of several cyanine dyes. Analysis by UV-Vis spectrophotometry led to calculation of λmax values for each dye, and values were compared to electronic spectra generated with the HyperChem program. The effective box length, a, was determined for six cyanine dyes and compared to the expected geometric box length, a...

Astaxanthin (AXT) is a natural carotenoid which provides colorations to numerous living species such as salmon. Owing to its chelate function deprotonated astaxanthin (axt−) should be easily attached to metal ions. The complex Rh(phpy)2(axt) with phpy− = deprotonated 2-phenylpyridine was prepared, and its electronic spectra and photochemistry were examined and compared to that of free AXT. Alth...

A new series of 12 complexes of cobalt(II) and nickel(II) with N-isonicotinamido-2',4'-dichlorobenzalaldimine (INH-DCB) with the general composition MX(2) . n(INH-DCB) [M = Co(II) or Ni(II), X = Cl(-) ,Br(-), NO(3) (-), NCS(-), or CH(3)COO(-), n = 2; X = ClO(4) (-), n = 3] have been synthesized. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental anal...

A hot phonon bottleneck may be responsible for slow hot carrier cooling in methylammonium lead iodide hybrid perovskite, creating the potential for more efficient hot carrier photovoltaics. In room-temperature 2D electronic spectra near the band edge, we observe amplitude oscillations due to a remarkably long lived 0.9 THz coherent phonon population at room temperature. This phonon (or set of p...

There is growing interest in engineering the properties of fluorescent proteins through modifications to the chromophore structure utilizing mutagenesis with either natural or unnatural amino acids. This entails an understanding of the photophysical and photochemical properties of the modified chromophore. In this work, a range of GFP chromophores with different alkyl substituents are synthesiz...

A series of Tb3+, Eu3+-doped Sr2MgSi2O7 (SMSO) phosphors were synthesized by high temperature solid-state reaction. X-ray diffraction (XRD) patterns, Rietveld refinement, photoluminescence spectra (PL), and luminescence decay curves were utilized to characterize each sample's properties. Intense green emission due to Tb3+ 5D4→7F5 transition was observed in the Tb3+ single-doped SMSO sample, and...

the aim of this research was to identify the life form spectra in the irano-tourani region. identifying these spectra can reveal the relevant life form species. by comparison these spectra with other regions, life form spectra, the situation of this region among the other regions can be determined. it was carried out using raunkiaer’s method to determine the life form spectra from irano-tourani...

based on the standards for design of structures, any structure should be designated for seismic loads and any combinations containing seismic loads. for spectral analysis of a structure, the site effect is taken into account by considering its effects on the design spectra. because of different lateral and vertical stiffness of the soil layers underneath the structure, the design spectra are di...