Hardware and software for the automating atomic-absorption spectrometers AAS, S115, and saturn

We describe a modified GELIOS System intended to automate the atomic-absorption spectrometers AAS, S115, SATURN, and Perkin-Elmer 503. Software is prepared in the visual environment of programming DELFI-3 and functions under the control of Windows 95. A distinguishing feature of the GELIOS System is simultaneous search for the peak and area of the absorption signal, correction of the errors of measurements, automatic digital filtration of data, control of the time of operation of hollow-cathode lamps, measurement of spectra and the statistical resource of the service life of hollow-cathode lamps, use of different methods to construct a calibrating graph, the possibility of memorizing the data of the analysis in an archived file, and a formation of the report for printing. The system contains an electrovic data directory on atomicabsorption analysis in five volumes for 67 elements of the Mendeleev system. To whom correspondence should be addressed. “University” Science and Production Center, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 734–737, September–October, 1999.     

Measurements of luminescence decay kinetics using an “Agat” streak-camera in a boxcar mode

Conclusion The specialized measuring setup described in the paper makes it possible to measure correctly and with reasonably high accuracy the luminescence decay kinetics of dyes within the time range from 40 psec to 5 nsec upon excitation in the visible range and at 1.064 μm. The system is highly flexible, having at the same time reasonably large data storage memory, and is completely automated. Such a system, undoubtedly, will be helpful for researchers working in the field of physics of laser media and dyes—passive modulators for femtosecond laser systems. The authors are grateful to M. V. Bondar for fruitful discussions and for help with the experiments. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 1, pp. 128–134, January–February, 1995.     

Transverse discharge with prebreakdown ionization multiplication of electrons in the working media of N2- and HF-lasers

Results of an investigation of the characteristics of a transverse discharge with prebreakdown ionization multiplication of electrons in the working media of N₂(C-B)-and SF₆/H₂ chemical HF-lasers are reported. The conditions of initiation of a stable volume discharge in the discharge gap with low homogeneity of the electrical-field distribution are investigated. A quasisteady plasma based on N₂ molecules with a radiation duration of ≤0.5 μsec at transitions of the 2⁺-system and a homogeneous discharge in a SF₆/H₂=(3–7)/(1–2) kPa mixture, which is of interest for preionization of the working medium of an HF-laser by the predischarge method, are obtained. Uzhgorod State University, 46, Pidgirna Str., Uzhgorod, 294000, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 412–415, May–June, 1999.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Influence of nonplanar distortions of the tetrapyrrole macroring on the electronic states of porphyrin dications

Quantum-chemical calculations of the excited electronic states of a porphyrin dication have been performed by the CNDO/S method for different angles determining the saddle-like and ruffled distortions of the porphyrin macroring. It is shown that saddle-like distortions arising as a result of a tilt of the pyrrole rings have a significant influence on the energies of the molecular orbitals and energies of the excited electronic states of porphyrin molecules, especially on the oscillator strength of the G→Q transition. The results of the calculations performed are in good agreement with the experimental spectra of porphyrin dications. To whom correspondence should be addressed. Reported at the VIIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 559–562, July–August, 1999.     

The effect of electron irradiation on the optical properties of the natural armenian zeolite-clinoptilolite

Infrared (IR) absorption and luminescence in chemically and radiation-modified natural Armenian Zeolite (clinoptilolite) samples have been studied. The luminescence was studied in 390–450 nm and 620–710 nm wavelength bands, and the IR measurements were carried out in the 400–5400 cm⁻¹ range. It is shown that the luminescence intensity depends on the content of pure clinoptilolite in the samples and, probably on the distribution of “passive” luminescence centers over Si and Al sites that became “active” under radiation or chemical treatment. The samples of electron irradiated clinoptilolite have higher luminescence intensity than the chemically and thermally treated ones. A decrease in the intensity of IR absorption bands at 3550 cm⁻¹ and 3650 cm⁻¹ was found after irradiation.     

The width of the rotational contour of vibrational and vibronic bands of complex molecules in the gas phase as a temperature indicator

From the independence of the contour of spectral density of the rotational (orientation) correlation function of a rigid molecular top of arbitrary symmetry on temperature in the frequency scale based on the reduced time of rotational orientation relaxation and from the near independence of the rotational contour of vibrational and vibronic absorption bands of dipole transitions in the same coordinates in a model of “regular diffusion” of the transition oscillator with a classically rotating rigid molecular top, it is suggested that it is possible to use the halfwidth of the contour for estimation of temperatures. Data are presented on the halfwidth of 48 contours of bands of A, B, and C types at this frequency for 12 compounds for a temperature range of from units to 500 degrees of absolute temperature measured experimentally and (for low temperatures) calculated by the quantum theory. Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 312–317, May–June, 1997.     

Rotation of the light polarization plane by an ensemble of oriented linear associates: Model representations

In an “oriented gas” model expressions are obtained for the angle of nongyrotropic rotation of the polarization plane (NRPP) of transmitted light by an ensemble of oriented associates consisting of nongyrotropic molecules. The cluster character of the nongyrotropic rotation of the polarization plane and the dependence of its angle on the incident light polarization vector azimuth are noted, which distinguish linear and circular polarization effects. Measurement of linear dichroism by the angle of nongyrotropic rotation of the polarization plane with the use of commercial spectropolarimeters is theoretically justified. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072 Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 95–101, January–February, 1998.     

Remote spectrophotometry as applied to determination of the degree of mineralization of peat soils in polesie

Regression relations between the first main component, slope of the SBC curve towards the wavelength axis, and the degree of mineralization of peat soils are established from experimental data. Errors in determination of peat soil productivity are estimated using different spectral indices. For practical use it is recommended to measure the spectral brightness coefficients of peat soils in the 0.50–0.75 μm range. B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 102–106, January–February, 1998.     

Control of the shape and duration of a laser pulse in the case of nonlinear total internal reflection

A nonlinear device based on nonlinear total internal reflection is suggested which provides a more than ten-fold shortening of the laser pulse and smooth variation of the pulse duration due to double reflection from the interface between transparent and absorbing media. Results are presented for the shape and duration of the pulse components that have been reflected and transmitted by the interface. B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., 220072, Minsk, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 325–328, May–June, 1997.     

Spectral reflection characteristics of spruce needles and leaves of trees in the zones with industrially polluted air

We analyze the results of laboratory measurements for the reflection spectra of spruce needles and maple leaves from zones with different degrees of air pollution by SO₂ and NO_x oxides. The calculated first derivatives and vegation indices are discussed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 789–792, November–December, 1997.     

Investigating the chromophore composition of wood pulps in thermoaging by diffuse reflection

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 1, pp. 81–85, January–February, 1995.     

Picosecond dynamics and mechanism of the interaction of a photoexcited Cu(II)-porphyrin with a DNA-modeling polynucleotide

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 2, pp. 110–121, March–April, 1995.     

The nature of empirical constants in the equation relating the frequency of the stretching vibration of oh-groups to parameters of the [MO n ]-polyhedrons coordinating these groups

Institute of Physicoorganic Chemistry, Academy of Sciences of Belarus, 220603, Minsk, Ul. Surganova, 13, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 1, pp. 104–107, January–February, 1995.     

Effect of oxygen on the optical properties of ZnSe in the region of 0.44–20 μm

Moscow Power Engineering Institute, 14, Krasnokazarmennaya Str., Moscow, GSP, 105835, Russia. Translated from Zhurnal Prikladnois Spektroskopii, Vol. 63, No. 4, pp. 646–651, July–August, 1996.     

Exciton transitions in photoluminescence spectra of AIAs/GaAs superlattices

Conclusions The studies performed here have shown that the superlattice samples studied exhibit photoluminescence spectra which agree with the Kronig-Penney model, although in calculating the energies of the radiative transitions it is necessary to take into account the binding energy of the excitons,E _B. Due to the exciton—phonon interaction, the 1HH peak breaks up on the long wavelength side into a Poisson distribution. The energy of the LO phonon so determined is 34 meV. Bands due toD ⁰-A ⁰ andD ⁰X transitions, caused by remaining low-level impurities in the GaAs crystals are also observed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 61, Nos. 3–4, pp. 241–245, September–October, 1994.     

Influence of a metal surface on the luminescence of adsorbed europium compounds

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 130–134, November–December, 1995.     

Photosensitized formation of singlet oxygen by vitamins of the B group

Presented at the XV IUPAC Symposium on Photochemistry, Prague, July 17–22, 1994.     

Investigation of the intramembrane distribution of chlorin e6 derivatives by using fluorescence quenching

Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 2, pp. 179–187, March–April, 1995     

Unsteady-state methods of investigation of the heterogeneous chemiluminescence of phosphor crystals

Priazovskii State Technical University, Pereulok Respubliki 7, Mariupol 341000, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 210–214, May–June, 1995.