Fluorescence spectroscopy has been demonstrated to be a powerful tool for characterizing phytoplankton communities in marine environments. Using different fluorescence spectra techniques, it is now possible to discriminate the major phytoplankton groups. However, most of the current techniques are based on fluorescence excitation measurements, which require stimulation at different wavelengths ...

Open-shell complexes that involve radicals in orbitally degenerate states exhibit weak-field Renner-Teller coupling effects. The CH(A )-Ne complex is an interesting example as both the anisotropy of the intermolecular potential energy surface and the spin-orbit coupling constant are small. The level splittings produced by the interaction with Ne produce a dense manifold of states. Consequently,...

Fast identification of pesticide residue level in lettuce leaves plays a key role in the test of food safety. In order to identify the different concentrations pesticide residues of lettuce leaves in a fast and nondestructive way, the hyperspectra coupled with chlorophyll fluorescence spectra was used in this research. Transmission electron microscopy (TEM) was used to identify the microstructu...

The quenching of trans-1-(2-anthryl)-2-phenylethene (t-APE) fluorescence by fumaronitrile (FN) was determined as a function of excitation wavelength (λexc) and temperature (5.0 e T e 80.0 °C). Principal component analysis with self-modeling (PCA-SM) was applied separately to the fluorescence spectra at each temperature. Resolved pure conformer fluorescence spectra were based on the condition th...

In the present work, we examine normal and malignant stage IIIB cervical tissue by laser induced fluorescence, with 2 different objectives. (i) Development of the fluorescence spectroscopy technique as a standard optical method for discrimination of normal and malignant tissue samples and, (ii) Optimization of the technique by the method of matching of a sample spectrum with calibration sets of...

Several phycobiliproteins were prepared chromatographically pure and their absorption, fluorescence-emission, fluorescence-excitation and fluorescence-excitation polarization spectra determined. Changes in these spectra with ionic strength of the aqueous medium and chromoprotein concentration were interpreted in terms of interchromophore energy transfer and protein subunit equilibria. The compl...

Fluorescence excitation spectra for transition à Au – X̃ Ag of trans-glyoxal in a supersonic jet were recorded with laser excitation in a wavelength region near 395 nm. With resolution 0.04 cm, most lines in these spectra are resolved and are assigned rotationally; of six bands assigned, three have c-type rotational structure, and another three have types a/b hybrid, a and b . Fluorescence decay...

Aqueous ions are central to catalysis and biological function and play an important role in radiation biology as sources of damage-inducing electrons. Detailed knowledge of solute-solvent interactions is therefore crucial. For transition-metal ions, soft X-ray L-edge spectroscopy allows access to d orbitals, which are involved in chemical bonding. Using this technique, we show that the fluoresc...

The photoelastic modulation-reflection absorption infrared spectrum ~PEM-RAIRS! of CO on single crystal Pd~111! is measured for CO pressures up to ;150 Torr. The ac component of the signal, corresponding to the infrared signal of the surface, is measured using a synchronous demodulator circuit rather than using a lock-in amplifier as used in previous experiments to measure the infrared spectra ...