A finite element procedure of the second order of accuracy

A finite element procedure of the second order of accuracy for solving second order boundary value problems is presented and justified and numerical results are given.     

Microwave heating of electrons of a dense plasma column at frequencies higher than electron cyclotron frequency

In this experimental study the absorption of plasma waves, excited in a dense plasma column, was investigated and the localization of the regions of efficient heating of electrons were determined in a broad range of parameters: 1>_ce/>0·1, 0·3<n/n _UH <25, 10^–5<v/< <10^–3. The heating of electrons near the second electron cyclotron harmonic was investigated in greater detail.We are grateful to the members of the Staff of the Institute of Plasma Physics Drs. P.unka, R.Klí'ma, V.Kopecký, J.Musil for discussion of the results. We also thank Drs. J.Musil, F.áek for the help and advice in the early stages of experimental work during construction of different diagnostic devices. Our thanks are due to the director of the Institute Dr. J.Váa for encouraging support of this experimental program.     

Analysis of Weinberg's algebraic relations

Implications of Weinberg's algebraic relations when only p-wave pions are taken into account are investigated. It is shown that decay rates and mass spectra of hadrons assigned to certain classes of unitary irreducible representations of theSU(4) group are in a strong disagreement with experimental data.     

On the role of the image potential in electron surface studies

Exchange and correlation contributions to the vacuum part of the effective electron potential of a semiinfinite crystal are modelled by a simple shifted image potential. Modifications, introduced by this potential, are studied for the cases of electron surface states and of the diffraction of low-energy electrons on a simple one-dimensional model.     

Semiempirical versusab initio calculations of molecular properties

A comparative study of the structural parameters in some strained spirohydrocarbons is presented. The theoretical values provided by the STO-3G, MINDO/3 and IMOA methods are in reasonable agreement with each other and with available experimental data offering thus a posteriori justification of the employed approximate schemes.     

Inversion and inversion-rotation spectrum of 14NH3 in the ν2 excited state

Using the vibration-inversion-rotation Hamiltonian for ammonia [V. ?pirko, J. M. R. Stone, and D. Papou?ek, J. Mol. Spectrosc.60, 159–178 (1976)], a modified theory is worked out for the Δk = ±3n interactions between the inversion-rotation energy levels of NH₃ which takes into account the large amplitude inversion motion. Eighty frequencies of inversion and inversion-rotation transitions and two perturbation-allowed transitions in the ν₂ state of ¹⁴NH₃ are measured in the far-infrared region around 1 THz (≈33 cm^?1), mostly with the microwave accuracy, by the radiofrequency spectrometer with acoustic detector. By a least-squares fit of these data and the data of the infrared-microwave two-photon and infrared heterodyne measurements of the ν₂ band, a set of molecular constants for the ν₂ state of ¹⁴NH₃ is obtained which reproduces the submillimeterwave data with the accuracy of the experiment.