Search results

1

Analysis of the Origin Band of Acridine Dimer Fluorescence Excitation Spectrum - Conformations of Jet-Cooled Acridine Dimer

100%

Deperasińska I., Prochorow J.

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EN

The analysis of rotational band contour for the origin transition of fluorescence excitation spectrum of acridine dimer, earlier observed under conditions of jet-cooling in supersonic helium expansion, has been performed. An optimized ground-state equilibrium structure of acridine dimer fits the approximation of asymmetric top rigid rotor. In this approximation rotational constants were determined and an A-type rotational band was computed. It has turned out that the computed rotational band contour is much narrower than the experimental one. In search for the reasons of this discrepancy between calculations and experiment, an analysis of relative rotational motion of acridine moieties of the dimer was carried out. It was found that minima of potential energy curves for rotational motion, although very flat, under conditions of supersonic expansion can acquire (in their shallow local minima) non-vanishing population of slightly different conformations of the dimer. It was shown that in terms of non-statistical distribution of such populations, the origin bands of individual conformations may contribute to the experimental band contour.

2

Long-range Interactions for the A^31_u and B^30^+_u States of Cd_2 from Line Shape Measurements

80%

Grycuk T., Michalicka M., Rogaczewski J.

Acta Physica Polonica A

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2002

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vol. 101

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issue 6

825-836

EN

We report on very precise measurements of the absorption profile of the 326.1 nm resonance line of cadmium broadened by interactions with the ground state Cd atoms under thermal equilibrium. The experimental red wing profiles, corrected for the Boltzmann factor at different temperatures, are analysed in terms of the long-range potential parameters including dispersion and resonant interactions. The resonant interaction energy constant C_3 is calculated to be 2.31×10^{-2} eV Å^3 and the van der Waals constant C_6 for difference potentials between the ground state X^10^+_ g and the excited states B^30^+_u and A^31_u of Cd_2 derived experimentally are found to be (182.6± 8) eV Å^6 and (289±4) eV Å^6, respectively. The former is determined for the first time and the latter is considerably corrected in comparison to earlier determination. The van der Waals constant C_6 for the ground state of Cd_2 is discussed and estimated to be C_6^g=(247± 40) eV Å^6.

3

Collision-Time Asymmetry and Speed-Dependent Effects on the ^{114}Cd 326.1 nm Line Perturbed by Kr

80%

Trawiński R., Bielski A., Lisak D.

Acta Physica Polonica A

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2001

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vol. 99

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issue 2

243-256

EN

Using a laser-induced fluorescence method, detailed analysis of profiles of the ^{114}Cd 326.1 nm line perturbed by krypton was performed which revealed departures from the ordinary Voigt profile. These departures are shown to be consistent with fits of experimental profiles to a speed-dependent asymmetric Voigt profile. Coefficients of the pressure broadening, shift, and collision-time asymmetry are determined and compared with those calculated in the adiabatic approximation for the van der Waals, Czuchaj-Stoll, and Morse potentials.

4

Pressure Broadening and Shift of the 326.1 nm Cd Line Perturbed by H_{2} and D_{2}

80%

Bielski A., Ciuryło R., Domysławska J., Lisak D., Trawiński R., Wolnikowski J.

Acta Physica Polonica A

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2000

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vol. 97

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issue 6

1003-1010

EN

The experimental values of pressure broadening and shift coefficients of the ^{114}Cd 326.1 nm line perturbed by H_{2} and D_{2} are determined using a LIF technique and compared with theoretical values calculated from the impact theory.

5

Effects of Low-Polarizability Perturbers on the Cadmium Intercombination Line

80%

Bielski A., Lisak D., Trawiński R., Szudy J.

Acta Physica Polonica A

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2003

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vol. 103

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issue 1

23-40

EN

Using a laser-induced fluorescence method a detailed analysis of profiles of the ^{114}Cd 326.1 nm line perturbed by neon and helium was performed which revealed deviations from the ordinary Voigt profile. These deviations are shown to be consistent with fits of experimental profiles to an asymmetric Voigt profile. Coefficients of the pressure broadening, shift and collision-time asymmetry are determined and compared with those calculated in the adiabatic approximation for different interaction potentials.

6

Influence of Excitation Processes on the Shape of Argon and Neon Lines

80%

Bielski A., Ciuryło R., Lisak D., Trawiński R.

Acta Physica Polonica A

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2000

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vol. 97

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issue 2

275-284

EN

Shapes of self-broadened argon lines 687.1 nm (4d_{5}-2p_{10}), 703.0 nm (3s_{5}-2p_{9}), 750.3 nm (2p_{1}-1s_{2}) as well as the neon line 748.8 nm (3d_{3}-2p_{10}) emitted from glow discharges at low pressures were analysed using a Fabry Perot interferometer. We showed that the dissociative recombination of Ar^{+}_{2} (or Ne^{+}_{2}) molecular ions which gives rise to the density of non-thermalized atoms, may be regarded as the main process responsible for the distortion of the profiles of the above lines. The distorted profiles were analysed as superposition of the Ballik profile for thermalized atoms and the modified Ballik profile for non-thermalized atoms. The Lorentzian and Gaussian widths as well as relative densities of non-thermalized and thermalized atoms were determined.

7

Spectroscopy and Photophysics of Monoazaphenanthrenes I. Absorption and Fluorescence Spectra of Phenanthridine and 7,8-Benzoquinoline

80%

Norek M., Dresner J., Prochorow J.

Acta Physica Polonica A

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2003

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vol. 104

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issue 5

425-439

EN

The absorption and fluorescence spectra of phenaentridine and 7,8-benzoquinoline have been measured in liquid solutions of non-polar, aprotic hydrocarbon solvents (n-hexane and cyclohexane) and in strongly polar (and hydrogen-bonding) methanol. The analysis of the Stokes' shift between absorption and fluorescence spectra has shown that for both molecules the observed solvent effects on their absorption and fluorescence spectra can be described in terms of universal solvent-solute interactions (no evidence of specific solvent-solute interactions, of the type of hydrogen bond formation with participation of lone-pair electrons of nitrogen atom, has been found). On the other hand, the measured decay time profiles of fluorescence are visibly longer in methanol solution than in non-polar, aprotic solvents and these observations are consistent with the observed increase in fluorescence intensity of both molecules in strongly polar methanol solution. The radiative lifetimes of the first excited singlet state do not differ noticeably for both molecules, but it has turned out that in the case of phenanthridine the nonradiative processes are getting less effective in methanol solution than in the case of 7,8-benzoquinoline, which can presumably be related to the role of different position of the substitution of nitrogen atom in these two molecules.

8

Non-Adiabatic Semiclassical Calculations of the Collision-Time Asymmetry of the ^{114}Cd 326.1 nm Line Perturbed by Noble Gases

80%

Bielski A., Ciuryło R., Lisak D., Trawiński R., Orlikowski T.

Acta Physica Polonica A

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2004

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vol. 105

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issue 3

217-232

EN

The collision-time asymmetry coefficients as well as the pressure broadening and shifting rates of the ^{114}Cd 326.1 nm line perturbed by noble gases are calculated in the framework of the non-adiabatic semi-classical method using the Czuchaj et al. potentials. The theoretical values are compared with experimental results determined recently by means of laser-induced fluorescence technique.

9

Observation of the Line-Mixing and Collision-Time Asymmetry of the 5^{1}S_0-5^{3}P_1 Line of the Even-Odd ^{113}Cd Isotope

80%

Bielski A., Ciuryło R., Domysławska J., Lisak D., Masłowski P., Szudy J., Trawiński R.

Acta Physica Polonica A

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2004

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vol. 105

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issue 4

329-338

EN

The profiles of argon perturbed components of the 5^{1}S_0-5^{3}P_1 line of the even-odd ^{113}Cd isotope were measured using a laser-induced fluorescence method. It was shown that the asymmetries of the profiles are due to both the collision-duration and line-mixing effects.

10

Speed-Dependent Effects on the 748.8 nm Ne Self-Broadened Line

80%

Ciuryło R., Bielski A., Brym S., Domysławska J., Lisak D., Szudy J., Trawiński R.

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vol. 96

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issue 3-4

359-372

EN

Profiles of the self-broadened 748.8 nm Ne line emitted from a glow discharge in neon in the pressure range between 0.8 and 100 Tr were measured using an improved experimental setup with pressure-scanned Fabry-Perot interferometer. First, line profiles were analysed using an ordinary Voigt procedure which yielded the Doppler widths decreasing with the increase in neon pressure. Using a speed-dependent Voigt profile it was shown that for the 748.8 nm line the correlation between the Doppler and collisional broadening plays an important role. However, the values of the pressure broadening and shift coefficients determined by the speed-dependent Voigt analysis were found to be only slightly different from those obtained by the ordinary Voigt analysis. A systematic error in the determination of perturber concentration in our previous investigation was corrected.

11

Long-Range Interactions and the Oscillator Strength for the 1_u, 0^+_u → X 0^+_g Transitions in Zn_2

70%

Kubkowska M., Szczęśniak T., Grycuk T.

Acta Physica Polonica A

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2004

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vol. 105

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issue 4

317-328

EN

The interaction potentials for Zn_2 electronic states {1}_u and {0}_u^+ correlated with (4 {1}^P_1+4 {1}^S_0) asymptote in the long-range region (10-25) Å and the oscillator strength f for the absorption transition to these states are derived experimentally from a careful analysis of the self-broadened resonance 213.8 nm line of Zn. It is found that although the interatomic interactions at so long distances are dominated by resonance potential of the form C_3/R^3 resulting in the Lorentzian line shape, the parameter C_3 and thus f value significantly decrease with R decreasing. This effect proved to be a linear function of R^{-1} yielding the oscillator strength for the considered line f_0=1.456 ± 0.010 from R → ∞ extrapolation. This value seems to be the most accurate experimental result as yet and shows that the best theoretical values for this quantity are overestimated. It is suggested that the long-range behaviour of the potential energy curves observed here for the first time represents the effective potentials including dominating resonance interactions and a possible slight contribution of the dispersion interactions as well as the R-dependent spin-orbit interaction.

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Analysis of the Origin Band of Acridine Dimer Fluorescence Excitation Spectrum - Conformations of Jet-Cooled Acridine Dimer

Long-range Interactions for the A^31_u and B^30^+_u States of Cd_2 from Line Shape Measurements

Collision-Time Asymmetry and Speed-Dependent Effects on the ^{114}Cd 326.1 nm Line Perturbed by Kr

Pressure Broadening and Shift of the 326.1 nm Cd Line Perturbed by H_{2} and D_{2}

Effects of Low-Polarizability Perturbers on the Cadmium Intercombination Line

Influence of Excitation Processes on the Shape of Argon and Neon Lines

Spectroscopy and Photophysics of Monoazaphenanthrenes I. Absorption and Fluorescence Spectra of Phenanthridine and 7,8-Benzoquinoline

Non-Adiabatic Semiclassical Calculations of the Collision-Time Asymmetry of the ^{114}Cd 326.1 nm Line Perturbed by Noble Gases

Observation of the Line-Mixing and Collision-Time Asymmetry of the 5^{1}S_0-5^{3}P_1 Line of the Even-Odd ^{113}Cd Isotope

Speed-Dependent Effects on the 748.8 nm Ne Self-Broadened Line

Long-Range Interactions and the Oscillator Strength for the 1_u, 0^+_u → X 0^+_g Transitions in Zn_2