Competition between decay and dissociation of core-excited OCS studied by X-ray scattering

We show the first evidence of dissociation during resonant inelastic soft X-ray scattering. Carbon and oxygen K-shell and sulfur L-shell resonant and non-resonant X-ray emission spectra were measured using monochromatic synchrotron radiation for excitation and ionization. After sulfur, L2,3 -> {\pi}*, {\sigma}* excitation, atomic lines are observed in the emission spectra as a consequence of competition between de-excitation and dissociation. In contrast the carbon and oxygen spectra show weaker line shape variations and no atomic lines. The spectra are compared to results from ab initio calculations and the discussion of the dissociation paths is based on calculated potential energy surfaces and atomic transition energies.Comment: 12 pages, 6 pictures, 2 tables, http://link.aps.org/doi/10.1103/PhysRevA.59.428

Chosen population parameters of Lymantria monacha L. in stands of the Tuczno Forest District subjected to chemical control treatments in 2003, and in those not exposed to such treatments

A dynamic increase in the nun moth (L. monacha L.) population was observed in the territory of the Tuczno Forest District. For this reason a large part of forest complexes was subjected to chemical control of this pest species. At the same time, the monitoring of larvae abundance was carried out by way of the checks of fallen excrements and counts of male butterflies caught in pheromone traps. In the later period a drastic decline in larvae population abundance was noted in both, stands subjected to control treatments and those not exposed to such treatments. The population of male butterflies of nun moth in 2003 was the least abundant since 1996 in both, stands subjected and not subjected to control treatments

Can the feeding of pine foliophage's larvae have positive effect on the functioning of stands?

Different foliophagous species are an inseparable element of forest biocoenoses. Besides damage to asimlatory apparatus of trees which has negative impact on stands the feeding of larvae also cause considerable fall of valuable organic matter onto the forest floor where it undergoes fast decomposition process thus having a positive effect on matter cycling in an ecosystem. Depending on larvae density in three crowns the mass of organic matter falling onto the forest floor can oscillate within wide limits. The decomposition of litterfall supplies the soil with valuable biogenes and microelements. In this situation there appears a "fertiliser effect" advantageous for stands at a simulataneous insignificant loss in assimilatory apparatus

The dependence of forest bed thickness on the age of pine stands growing on post-agricultural and forest soils

Forest bed layer developing in a tree stand plays a very important part in functioning of forest ecosystem and is of key importance in soil carbon accumulation. In two different study objects (Niedźwiady and Tuczno), 351 forest bed thickness measurements were taken in 117 pine stands of different age classes, separating them into those growing on forest lands (28 tree stands – 84 measurements) and those on post−agricultural ones (89 tree stands – 27 measurements). The above relationships were analysed, what showed a relation between the thickness of forest bed and the age of tree stand. Forest bed thickness increases together with tree stand age, both on forest and post−agricultural soils

Ocena występowania larw barczatki sosnówki (Dendrolimus pini L.) w latach 1999-2003, w drzewostanach Nadleśnictwa Tuczno

The pine lappet moth (Dendrolimus pini L.) has been present in Poland's forests since many years. In 1999−2002, a violent increase in population number of this pest was noted in many regions of the country. In that period the monitoring of pine lappet moth population was carried out also in the stands of the Tuczno Forest District. The presence and density of larvae in tree crowns was established on the basis of the counts of fallen excrements. Obtained results clearly point to a dynamic increase in number of larvae in tree crowns until 2002. The excrement fall control accounted for an increase in percentage of colonised stands on the one hand and a gradual increase in density of larvae in tree crowns on the other one

Structure Dependence of Hyperpolarizability in Octopolar Molecules

Recent Hyper Rayleigh Scattering measurements report a significant increase of second-order hyperpolarizability upon introduction of positive charges at the pyridyl end groups in trispyridyl octopolar chromophores. We calculated the geometries, linear response, and first-order hyperpolarizabilities of a series of six trispyridyl molecules both in the neutral and protonated forms. The calculations were performed with ab initio and semiempirical methods. The results are in good agreement with the experimental values and a correlation between the first hyperpolarizability and two structural properties, the N−C bond elongation and the C−C bond length alternation, Δr was established. To test these effects we computed the hyperpolarizability for several constrained geometries and confirmed the importance of planarity on the hyperpolarizability values. However the Δr values alone seem to have little influence both on the hyperpolarizability and on the gap values. Replacing the triple C≡C bond by a double C=C bond in the conjugation bridge has no significant effect due to the strong hyperpolarizability dependence on the pyridyl-benzene dihedral angle