Vibrational spectra of La@C60 and Ce@C60 endohedral fullerenes: Influence of spin state multiplicity.

Endohedral fullerenes with paramagnetic encapsulated atoms are new magnetic materials of interest for numerous applications from medicine to quantum computers. An important phenomenon with endohedral fullerenes is the appearance of new vibrational frequencies not associated with empty fullerenes. The vibrational spectra of the lanthanide endohedral fullerenes La@C60 and Ce@C60 in various spin states are calculated using the density functional method. Most of the spectral lines lie in the 300-1600 cm-1range, and their intensities change dramatically depending on the molecule's symmetry and spin state, which are determined by the encapsulated lanthanide atom. The average frequency shift of the carbon cage vibrations caused by spin transition is only 5 cm-1. The calculated frequencies of the coupled "metal-carbon cage" vibrations of the lanthanide endohedral fullerenes La@C60 and Ce@C60 in various spin states lie in the 10-170 cm-1range. The computational results for both the frequencies and intensities of the metal-cage modes depend considerably on the spin state. The changes in these vibrational modes are due to the changes in the molecular symmetry and the metal-carbon bond lengths. Such dependence can be used as a basis for controlling the spin state of metallofullerenes by measuring the vibration frequencies in the far-infrared zone, which could be important for nanoelectronics and quantum informatics.

[The Nonlinear Effect of the Composite Influence of Red and Blue Light on Bacteria Escherichia coli Viability].

A non-linear dependence of the inhibition of E. coli cells is found when irradiated simultaneously with the blue and red regions of the spectrum at a power density of 100 mW/cm2. Such dependence is explained by the assumption of a cascade two-photon absorption of light by DNA molecules with an intermediate resonance at cellular chromophores, causing excitation and subsequent DNA damage similar to damage when exposed to UV radiation.

Ultrasoft x-ray Bremsstrahlung isochromatic spectra from 300-2000 eV electrons on Ar and Kr.

For the first time the bremsstrahlung effect was studied experimentally in the spectral region of 6.5-10 nm with 300-2000 eV electron scattering on Ar and Kr atoms. The isochromatic curves displayed maxima at electron energies of approximately = 0.7 keV (Ar) and approximately =1 keV (Kr); their positions are almost independent of the radiation wavelength in the range studied. These experimental data cannot be treated in the framework of theory based on the first Born approximation. A phenomenological modification of the quasiclassical (soft-photon) approximation is proposed which gives a qualitative treatment of data.

Effect of laser irradiation on functional activity of human neutrophils: activation of myeloperoxidase in the presence of hematoporphyrin.

Laser irradiation (lambda=540 nm) of the blood increased myeloperoxidase activity in polymorphonuclear leukocytes. We revealed photoinduced activation of myeloperoxidase in irradiated neutrophils in the presence of hematoporphyrin. The photodynamic effect was most pronounced, when the modifier was incorporated into the cell membrane or sorbed on it.