Fluorometry of natural latex from Maclura pomifera

Maclura pomifera is a small tree that produces rot-resistant wood and a strange fruit called an Osage orange which is bright green. The fruits contain a high content of latex with strong fluorescence in UV light, similar in color to the green-yellow fluorescence of uranyl glass. Measurements were made using a computer-assisted microscope with grating mono chromators in both excitation and emission pathways. A photomultiplier was calibrated using a tungsten illuminator, then a mercury illuminator was used to measure the fluorescence emission spectrum: the peak was at 530 nm (green-yellow). A xenon illuminator was used to measure the fluorescence excitation spectrum: the peak was at 380 nm (UV).

Прямое наблюдение квазилокализованной низкочастотной колебательной моды в спектре возбуждения флуоресценции одиночной примесной молекулы в полимерной матрице-=SUP=-*-=/SUP=-

The possibility of direct observation of a quasi-localized elementary excitation of the phonon type in polyisobutylene has been demonstrated by detecting the fluorescence excitation spectrum of a Mg‑tetrazaporphyrin single probe molecule in a wide spectral range at a temperature of 6 K. The parameters of the quasilocalized low-frequency vibrational mode have been measured—the frequency (energy) in the case, when impurity molecule is in excited electronic state (ω_ e = 13.94 ± 0.21 cm^–1) and the halfwidth of the mode spectrum (γ = 3.82 ± 0.66 cm^–1). The measured energy of the low-frequency vibrational mode coincides with the position of a boson peak maximum in the spectrum of vibrational states of the polymer, which indicates that the weak coupling approach can be applied to the considered case of the electron–phonon interaction of an organic dye molecule with the local environment in a polymer matrix.

The S1 ← S0 fluorescence excitation spectrum and structure of propanal in the S1 excited electronic state

Propanal molecule in the S1 excited electronic state has complex conformational structure.

Measurement of Absorption Spectrum of Media by Grating Spectrometer

In order to measure quantum yield (quantum efficiency) of light in the research of fluorescence excitation, rapid prototyping of micro-structure and photochemical, the absorption spectrum must be precisely measured. Therefore, the reflection on optical media interface, absorption and transmission in the medium must also be considered. In this article, we exhibit a set of reasonable experimental method which is designed to measure absorption spectrum by grating spectrometer. The results show that the obtained absorption lines are properly reliable if we select an appropriate way to settle the sample. Furthermore, it can be well generalized and applied to the selection of fluorescence excitation spectrum, photochemical reaction spectrum, photoelectric device spectrum.