60 years of the Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences

Wobec mijającego czasu i zmieniających się sytuacji geopolitycznych trwanie jest czymś niezwykłym, a jubileusze służą jako przystanki, by spojrzeć wstecz i w przyszłość. 60 lat działalności Instytutu Fizyki Jądrowej daje wiele powodów do dumy z jego osiągnięć i do radości z szerokich perspektyw na przyszłość. Warto co dekadę zatrzymać się, by dokonać podsumowań, zweryfikować plany i przyjrzeć się jak jesteśmy postrzegani w kraju i na świecie.To the passing of time and the changing geopolitical situation the duration is something unusual, and anniversaries let us to look back and to the future. 60 years of activity of the Institute of Nuclear Physics gives us many reasons to be proud of its achievements and to rejoice with its broad prospects for the future. Worth every decade to make summaries, verify the plans and look at how we are perceived in the country and the world

A Model Calculation of Infrared Spectra in Cyclohexanol

A model calculation based on semiempirical methods for the cyclohexanol molecules is presented. Energetically preferred molecular conformations and possibility of different hydrogen bond networks in the crystal are discussed. The calculated and the experimental infrared spectra are compared. The results corroborate earlier suggestions that the rich polymorphism of cyclohexanol is due to the existence of both axial and equatorial isomers in solid phases and different architecture of hydrogen bonds network

Elastic, quasielastic and inelastic neutron scattering studies on the CT hexamethylbenzene-acyanoquinodimethane complex

The 1:1 hexamethylbenzene (HMB)-tetracyanoquinodimethane (TCNQ) complex shows a first-order phase transition at 230/218 K (heating/cooling) with no change of the space group. The neutron-diffraction studies reveal that this transition is related to a freezing of the rotation of methyl groups. The results for 100 K enabled precise determination of configuration of HMB center dot TCNQ complexes. The planes of HMB and TCNQ molecules from small angle (6 degrees) so that the dicyanomethylene group approaches the HMB molecule to a distance of 3.34 angstrom. The conformation of methyl groups was exactly determined. The quasielastic neutron-scattering spectra can be interpreted in terms of 120 degrees jumps with different activation barrier in low- and high-temperature phases, equal to 3.7 and 1.8 kJ/mol, respectively. These values are lower than that for neat HMB (6 kJ/mol). The conclusion can be drawn that the methyl groups can reorient more freely in the complex. This conclusion is in agreement with the results of inelastic neutron-scattering studies of low-frequency modes assigned to torsional vibrations of methyl groups. These frequencies are lower than those for neat HMB. The analyzed increase of frequencies of these modes as compared with free molecules can be interpreted as due to formation of unconventional C-(HY)-Y-... hydrogen bonds which are more pronounced in crystals of neat HMB than in those of HMB(.)TCNQ. The low-frequency librational modes can be treated as a sensitive measure of unconventional hydrogen bonds formed by the CH3 groups. (c) 2005 American Institute of Physics