Showing papers by "Jagiellonian University published in 1976"

Crystal and magnetic structure of NiMnGe

Abstract: NiMnGe is investigated by means of X-ray diffraction, neutron diffraction, and magnetometric methods. The orthorhombic distorsion of hexagonal lattice is observed below 470 K. The compound NiMnGe is antiferromagnetic with a Neel temperature TN = 346 K. The jump observed at temperature Tt = 185 K on the temperature dependence of magnetic susceptibility points at the change of a magnetic structure. From the analysis of the neutron diffraction patterns the following models of spiral magnetic structure are obtained; at T < Tt the spiral axis is in the bc-plane. The angle between the spiral axis and the b-axis is 45°, magnetic moment at 80 K is 2.75μB; at Tt < T < TN the spiral axis is along the a-axis. The magnetic moment at 295 K is 2.2μB.

Theory of the infrared spectra of the hydrogen bond in molecular crystals

Abstract: A general model for the vibrational interactions of the hydrogen bonds in molecular crystals is presented. The energy and the intensity distributions of the IR spectra of the 1-methylthymine and uracil crystals are correctly reproduced.

Model considerations of the light conditions in noncylindrical plant cells

Abstract: — A geometric model of a noncylindrical plant cell has been constructed using optical and geometrical parameters obtained for the cells of Funaria hygrometrica and Lemna trisulca leaves. The distribution of the incident light intensity and the absorption profile in the monomolecular photoreceptor layer on the walls of the model cell irradiated with the parallel beam have been calculated. Calculations were performed for two surrounding media with refractive indices of 1.33 (water) and 1.00 (air). Various chloroplast arrangements were considered. The course and kinetics of the phototactic movements of Funaria and Lemna chloroplasts have been discussed on the basis of the results obtained. The best agreement between the theoretical and experimental data is obtained by assuming that the transition moments at 450 nm of the dichroic photoreceptor molecules are oriented parallel to the surface of the cell wall.

Structural studies by 1H and 13C d.n.m.r.: I—barrier to trans-cis isomerization in aliphatic enamino ketones of the type R ? CO ? CHCH ? NHR1

Abstract: D.n.m.r. studies have been performed involving the measurement of rates of trans-cis isomerization of aliphatic enamino ketones of the type RCOCHCHNHR1, by means of equilibration experiments and the method of finding the coalescence temperature. Simultaneous observation of the rates of dynamic NH proton exchange and isomerization processes by the latter method has facilitated the assignment of the rate-determining reaction step in the title compounds studied in aprotic solvents. Thermodynamic parameters are discussed and the dipolar transition state to isomerization in a nonpolar solvent indicated. The dynamic behaviour of all protons undergoing exchange between the possible sites in the molecule are discussed in the light of our own experiments and other recent data.

Entropy per particle in the early Bianchi type-I Universe

Abstract: We consider the behaviour of the radiation entropy per particle in the early stage of the Universe according to the Bianchi type I in which there are nonvanishing terms for the shear viscosity in the energy-momentum tensorTμν. The viscosity coefficient η is a function of the temperature η=ωTm, where ω andm are constants. We rewrite Einstein equations in such a manner that we can analyse the influence of dissipation on the isotropization. Results of the above analysis reveal that, in the framework of the considered model, the effects of the shear viscosity appear to be significant only under very special initial conditions for the dissipation parameter and form<1; in such a case the radiation entropy increases in the course of the evolution by a substantial factor. The expansion is practically isoentropic in all the remaining cases. The dissipation parameters are found for the lepton and radiation epochs.

Stochastic NH3-rotation in [Ni(NH3)6](ClO4)2 crystals studied by the neutron incoherent scattering method

Abstract: Quasielastic neutron scattering were spectra measured for polycrystalline [Ni(NH3)6](ClO4)2. The spectra have been interpreted using models describing the stochastic NH3-rotational motions. The two models: 120°-jumps and the uniaxial rotational diffusion were used in the fitting procedure. The results of the fitting show that a preference should be given to the 120†-jump model. A comparison with an IR profile study was also made. Both the existence of 120°-jumps and the discontinuity in the correlation times observed at the phase transition can qualitatively be explained by the Bates and Stevens picture.

On finitely based consequence operations

Abstract: w O. Let T = (T, do, . . . , dn) be a free algebra of terms of some finite t y p e free genera ted b y an infinite set of var iables V ---{x0, xl , ...}. We shall use Greek lower case a, ~, . . . for terms and Greek upper case r T, . . . for sets of terms. The symbol V(q~) denotes the set of variables occurring in terms of r If X is a set then the symbols P(X), PI(X) denote the set of subsets of X and the set of finite subsets of X respect ively. A mapping C: P(T)->P(T) is a co~seque~we operation in T iff for every q), T c_ T, r c__ CC(r c__ C(r A consequence operat ion C is algebraic (or finite) iff for every r _ T, C( r = [_J CFI(r a consequence opera t ion C is struct~o'al iff for every qD c T, eeHom(T, T), sC(r _ C(sr If C is s t ruc tura l and algebraic then it is called standard. A rule is a subse t 0 PI (T) x T, a rule 0 is structural iff it is closed under subs t i tu t ions i.e. for every eEHom(T, T), if (~, a)EQ then (e r s (a ) )~ . A sequent is a pair <~,@ePI(T) • E v e r y sequent < r de termines a s t ruc tura l rule g(q~, a) = {(sr s (a ) ) : seHom(T, T)}. A rule 0 is called sequential if Q ---~(~, a) for some sequent ( r a}. E v e r y set of rules R determines a consequence opera t ion C R such t ha t for every r c T, CR(q~ ) is the smallest subse t of T containing q~ and closed under rules of R. A consequence opera t ion C is finitely based iff C = CR for some finite set R of sequent ial rules. I t should be no ted t ha t the not ion of f initely based consequence opera t ion is to be credi ted to R. Suszko [5] who in t roduced it under the name of f initely formalizable consequence relat ion (see [5] p. 198). In the sequel we shall use the following well-known results :

Mixing of frenkel excitons and ionic excited states of a linear molecular crystal with two molecules in the unit cell I. General model

Abstract: The Merrifield theory of the interaction between the neutral and ionic excited states of a linear molecular crystal is generalized for crystals with two molecules in the unit cell. It is demonstrated that the Hamiltonian can be split into three communting terms. For two of them the original Merrifield theory is directly applicable and its conclusions are valid. The third term describes the mixing between the (+) Davydov component of the Frenkel exciton, the (+) intra-cell CT exciton, and the (+) lengthwise and (+) crosswise ionic pair states. It can no more be treated within the frame of the original Merrifield theory. However it can be further transformed to a renormalized form which consists of two decoupled Hamiltonians. Both of them are formally analogous to the Merrifield Hamiltonian but with renormalized effective parameters. In the result some ionic states become active in the absorption spectrum. Die Merrifieldsche Theorie der Wechselwirkung zwischen den neutralen und ionischen Anregungszustanden eines linearen Molekulkristalls wird fur Kristalle mit zwei Molekulen in der Einheitszelle verallgemeinert. Es wird gezeigt, das der Hamiltonoperator in drei kommutierende Terme separiert werden kann. Fur zwei von ihnen ist die ursprungliche Merrifieldsche Theorie direkt anwendbar und deren Schlusse bleiben gultig. Der dritte Term beschreibt die Mischung zwischen der (+)-Davydov-Komponente des Frenkelschen Exzitons, dem (+)-Intrazellen-CT-Exziton und den (+)-longitudinalen und (+)-transversalen Ionenpaar-Zustanden. Er kann nicht mehr im Rahmen der ursprunglichen Merrifieldschen Theorie behandelt werden. Jedoch last er sich weiter in eine renormierte Form transformieren, die aus zwei entkoppelten Hamiltonoperatoren besteht. Beide sind formal dem Merrifieldschen Hamiltonoperator analog, jedoch mit renormierten effektiven Parametern. Als Ergebnis werden einige Ionenzustande im Absorptionsspektrum aktiv.

Electron impact mass spectra of some enamines

Abstract: The mass spectra of α,β-diarylaminocrotonic acid anilides have been determined and the fragmentation pathways are now discussed. The proposed pathways have been confirmed by deuterium labelling, the spectrum of the model compound, or the appropriate metastables. The detailed electron impact data are given.

Macromycetes of meadows in Pieniny National Park

Abstract: The investigations were performed in the years 1968-1972 in the area of forest meadows ( Anthvllido-Triofolietum and Nardetum strictae ) on northern mountain slopes in Pieniny National Park. The phenological seasons were distinguished during the year. Attention was paid to the problem of fairy rings and to fungi which form them. The effects of atmospheric conditions on the fruiting of meadow fungi were examined. On 9 sample plots quantitative investigations were performed. Differences in the course of yearly fruiting of fungi between years poor in rainfall and normal ones were demonstrated. The degree of abundance of particular species of fungi was determined by index method of Perkal. The mycoflora of the examined association and the content of mycoflora of Pieniny meadows with meadow fungi of other mountain zones in Poland were compared.

Effective ElectronHole Interaction in Molecular Crystals II. Phonon Mechanism

Abstract: A possible mechanism of electronhole interaction via phonons in molecular crystals is considered. A linear approximation in the phonon operators is adopted. Possible conse- quences are discussed from the viewpoint of the stabilization energy of an ionized state, the equilibrium charge carrier concentration, and the charge carrier lifetime. Es wird ein moglicher Mechanismus der ElektronLoch-Wechselwirkung uber Phononen in Molekulkristallen betrachtet. Es wird eine lineare Naherung in den Phononenoperatoren angenommen. Mogliche Konsequenzen werden unter dem Gesichtspunkt der Stabilisierungsenergie des ionisierten Zustandes, der Ladungstragerkonzentration im Gleich gewicht und der Ladungstragerlebensdauer gezogen.

Roman Ingarden’s Moral Philosophy

Abstract: Two publications of Roman Ingarden deal directly and exclusively with ethical problems: ‘An Inquiry into Moral Values’1 (this is almost an exact record of one of his lectures on ethics held at the Jagiellonian University in 1961/62) and Ueber die Verantwortung 2 (an extended version of his lecture delivered at the International Philosophical Congress in Vienna in 1968). There are two more essays closely connected with those problems: ‘Remarks on the Relativity of Values’ (Uwagi o wzgled-ności wartości)3 and ‘What We Do Not Know about Values’ (Czego nie wiemy o wartoiściach); though they are devoted to the general theory of value, many considerations in them refer to the moral values. The way in which Ingarden approached ethics, its subject and aims, allows us to include his considerations on ontology and epistemology to the reconstruction on his ethics. To those materials there may be added several chapters from the book The Controversy about the Existence of the World 4 and two articles: ‘Man and His Reality’ (Czlowiek i jego rzeczywistośc)5 as well as ‘Man and Time’6. As to the above-mentioned lectures, only one of them was authorized and published by the author.

Mossbauer studies of the activation of ammonia synthesis catalysts

Abstract: Resume. — L'article presente des etudes Mossbauer de l'activation (reduction) de catalyseurs de commerce, bases sur magnetite et frequemment promotes, pour la synthese de l'ammoniac. Les etudes s'effectuaient sur deux catalyseurs contenant des quantites differentes (4 % et 27 %) de wustite. Le procede de reduction fut suivi de spectroscopie Mossbauer in situ permettant une etude des cinetiques de reduction. On a trouve que la phase wustite est reduite plus vite que la magnetite. Seulement le catalyseur qui retient la quantite moindre de wustite se trouvait reduit selon le modele noyau-et-coquille. Une comparaison avec des observations microscopiques elucide les desaccords susmentionnes. En contraste avec l'etude prealable de catalyseurs singulierement promotes, on a trouve sous conditions operatoires la presence de fer non reduit.

Effect of Polarization on Charge Carrier Transfer in Molecular Crystals

Abstract: The influence of the polarization of the molecular orbitals of a neutral molecule by the electric field of an ion on the charge carrier transfer integrals is investigated. A simplified crystal structure is assumed and the calculations are performed for a dimer model of the neighbouring molecules. The polarization effects are calculated in a scheme which does not involve the polarizability concept. Some essential differences with previous results are discussed. Es wird der Einflus der Polarisation der Molekulbahnen eines neutralen Molekuls durch das elektrische Feld eines Ions auf die Ladungstragertransferintegrale untersucht. Eine vereinfachte Kristallstruktur wird angenommen, und die Rechnungen werden fur ein Dimermodell der benachbarten Molekule durchgefuhrt. Die Polarisierungseffekte werden in einem Schema berechnet, das die Vorstellung der Polarisierbarkeit nicht einschliest. Einige wesentliche Unterschiede zu fruheren Ergebnissen werden diskutiert.

Effective Electron-Hole Interaction in Molecular Crystals (I)

Abstract: An effective electron-hole interaction is investigated which arises due to the one-particle exciton dissociation matrix elements of the Hamiltonian. Frohlich-type unitary transformation is adopted and the transformed Hamiltonian is discussed. The exciton energy is renormalized. The sign and absolute value of the effective electron-hole interaction is revealed to depend on the energy difference between the neutral exciton and charge transfer states. The influence of the vibronic coupling is also investigated. Es wird eine effektive Elektron-Loch-Wechselwirkung untersucht, die durch die Matrixelemente des Hamiltonoperators der Einteilchen-Exzitonen-Dissoziation hervorgerufen wird. Die unitare Transformation vom Frohlich-Typ wird benutzt und der transformierte Hamiltonoperator diskutiert. Die Exzitonenenergie wird renormiert. Es wird gezeigt, das das Vorzeichen und der absolute Wert der effektiven Elektron-Loch-Wechselwirkung von der Energiedifferenz zwischen dem neutralen Exziton und den Charge-Transfer-Zustanden abhangt. Der Einflus der vibronischen Kopplung wird ebenfalls untersucht.

Phase transitions and NH3 rotations in [Co(NH3)6]I3 studied by calorimetry and IR profile methods

Abstract: Specific heat versus temperature data for [Co(NH3)6]I3 show anomalies at 276.2 and 281.9 K. IR active NH3-rocking vibrations are used for band-profile study versus temperature, below and above the specific heat anomalies. The correlation times, τ1, for NH3 rotation about the CoN axis are measured and are of the order of picoseconds at room temperature. Barriers to NH3 rotation are different above (1.17 kcal/mole) and below (1.48 kcal/mole) the specific heat anomalies. Die Werte der spezifischen Warme uber der Temperatur zeigen fur [Co(NH3)6]I3 Anomalien bei 276,2 und 281,9 K. Fur die Bandenprofiluntersuchungen in Abhangigkeit von der Temperatur, unterhalb und oberhalb der Anomalien der spezifischen Warme, werden IR-aktive NH3-rocking-Schwingungen verwendet. Korrelationszeiten τ1 fur die NH3-Rotation um die CoN-Achse werden gemessen, die bei Zimmertemperatur die Grosenordnung von Picosekunden haben. Die Barrieren fur die NH3-Rotation sind oberhalb und unterhalb der Anomalien der spezifischen Warme unterschiedlich (1,17 kcal/mol bzw. 1,48 kcal/mol).

An adiabatic calorimetry study of the phases in solid D3O·ClO4

Abstract: Specific heat measurement performed for deuterated perchloric acid monohydrate (D3O·ClO4) led to the discovery of two anomalies: at 245.1 and 251.9 K. Entropies connected with these anomalies are 1.22 and 4.69 cal/mol K. A structural model based upon D3O+-ion configurations is suggested for the interpretation of the observed phase (situation).