UV-induced dissociation of CH2BrI probed by intense femtosecond XUV pulses

The ultraviolet (UV)-induced dissociation and photofragmentation of gas-phase CH2BrI molecules induced by intense femtosecond extreme ultraviolet (XUV) pulses at three different photon energies are studied by multi-mass ion imaging. Using a UV-pump — XUV-probe scheme, charge transfer between highly charged iodine ions and neutral CH2Br radicals produced by C—I bond cleavage is investigated. In earlier charge-transfer studies, the center of mass of the molecules was located along the axis of the bond cleaved by the pump pulse. In the present case of CH2BrI, this is not the case, thus inducing a rotation of the fragment. We discuss the influence of the rotation on the charge transfer process using a classical over-the-barrier model. Our modeling suggests that, despite the fact that the dissociation is slower due to the rotational excitation, the critical interatomic distance for charge transfer is reached faster. Furthermore, we suggest that charge transfer during molecular fragmentation may be modulated in a complex way.

Investigação do comportamento viscoelástico de amostras de licor negro oriundas do processo de polpação Kraft da Cenibra-MG à 25 oc

RESUMO O comportamento viscoelástico dos licores negros de eucalipto (LN) do processo de polpação Kraft da CENIBRA foi avaliado a 25 oC, na ausência (LNSC) e na presença (LNCC) de cinzas da ebulição da recuperação química, que são geralmente misturadas com licores negros para melhorar a eficiência da recuperação química. As amostras foram tosquiadas em campos rotativos e oscilatórios, mostrando os comportamentos de cisalhamento e cisalhamento dependentes da taxa de cisalhamento aplicada. A viscosidade complexa - *, o módulo de armazenamento e perda - G' e G'', e a tensão de rendimento 0 para LNSC foram todos muito superiores ao LNCC, provavelmente devido à fragmentação molecular causada pela adição de cinzas. ABSTRACT The viscoelastic behavior of eucalyptus black liquors (LN) from CENIBRA Kraft pulping process was evaluated at 25 oC, in absence (LNSC) and in presence (LNCC) of ash from chemical recovery boiling, which are usually mixed with black liquors to improve the efficiency of chemical recovery. The samples were sheared upon rotational and oscillatory fields, showing booth shear-thickening and shear-thinning behaviors dependent of applied shear rate. The complex viscosity – h*, storage and loss modulus – G’ and G’’, and yield stress s0 for LNSC were all very higher than LNCC, probably due the molecular fragmentation caused by addition of ashes.

A theoretical chemistry-based strategy for the rational design of new luminescent lanthanide complexes: an approach from a multireference SOC-NEVPT2 method

Theoretical methods of the SOC-NEVPT2 type combined with a molecular fragmentation scheme have been proven to be a powerful tool that allows explaining the luminescence mechanism in Ln(iii) compounds of the form Eu(R-phen)(BTA)3.

Multiple dehydrogenation of fluorene cation and neutral fluorene using the statistical molecular fragmenta- tion model

The statistical molecular fragmentation (SMF) model was used to analyze the 306 fragmentation channels (containing 611 different species) that result from the fluorene (C13H+10) cation losing up to three hydrogen...