High resolution slice imaging of nonadiabatic state-to-state photodynamics

Stolte, S. [Promotor]Janssen, M.H.M. [Copromotor

The rise of zombie firms and the slow recovery of the portuguese economy

Dissertação de mestrado em EconomicsThe slowdown in the economic growth of developed countries, the last financial crisis and the slow economic recovery have raised a lot of controversy as population is gradually more educated and technological innovations are getting each time faster. Thus, the study of zombie firms and their impact on the Portuguese economy is extremely important because of the link between these three major problems. This paper aims to determine the main causes of the appearance, fixation and increase of this type of firms in Portugal; its evolution and importance in the Portuguese business structure and the effects on healthy companies and the economy in general at different levels. The results demonstrate two important things: i) the zombie firms represent a congestion of market resources (mainly labor and capital), harming the other companies in the economy on both levels; ii) the higher the zombie share in a given industry, the greater will be the difference in productivity between the most dynamic companies and the laggards. That is worrisome because as the multi-factor productivity (MFP) gap increases, the greater is be the competition in the industry, and the harder it will be for new companies to enter in the market and replace the zombie ones. This is one of the barriers to enter in the market caused by the congestion of zombie firms and may be related to a slower recovery of the Portuguese economy after the financial crisis.A desaceleração do crescimento económico dos países desenvolvidos, a última crise financeira e a lenta recuperação económica geraram muita polémica, uma vez que a população é gradualmente mais instruída e as inovações tecnológicas são cada vez mais rápidas. Assim, o estudo das empresas zombie e o seu impacto na economia portuguesa é extremamente importante devido ao vínculo entre esses três problemas principais. Este trabalho pretende determinar as principais causas do aparecimento, fixação e aumento deste tipo de empresas em Portugal; a sua evolução e importância na estrutura empresarial portuguesa e os efeitos nas empresas saudáveis e na economia em geral a vários níveis. Os resultados demonstram duas coisas importantes: i) as empresas zombie representam um congestionamento de recursos de mercado (principalmente tabalho e capital), prejudicando as outras empresas da economia nos dois níveis e levando a uma forte emigração da população ativa portuguesa; ii) quanto maior a percentagem de zombies em um determinado setor, maior será a diferença de produtividade entre as empresas mais dinâmicas e as empresas com fraco desempenho. Esse resultado é preocupante, uma vez que à medida que aumenta a diferença de MFP, maior é a concorrência no setor e mais difícil será a entrada de novas empresas no mercado e a substituição de zombies. Esse é um dos obstáculos à entrada no mercado causados pelo congestionamento das empresas zombies e pode estar relacionado a uma recuperação mais lenta da economia portuguesa após a crise financeira

Fragmentation dynamics of the ethyl bromide and ethyl iodide cations: a velocity-map imaging study

The photodissociation dynamics of ethyl bromide and ethyl iodide cations (C2H5Br+ and C2H5I+) have been studied. Ethyl halide cations were formed through vacuum ultraviolet (VUV) photoionization of the respective neutral parent molecules at 118.2 nm, and were photolysed at a number of ultraviolet (UV) photolysis wavelengths, including 355 nm and wavelengths in the range from 236 to 266 nm. Time-of-flight mass spectra and velocity-map images have been acquired for all fragment ions and for ground (Br) and spin–orbit excited (Br*) bromine atom products, allowing multiple fragmentation pathways to be investigated. The experimental studies are complemented by spin–orbit resolved ab initio calculations of cuts through the potential energy surfaces (along the RC–Br/I stretch coordinate) for the ground and first few excited states of the respective cations. Analysis of the velocity-map images indicates that photoexcited C2H5Br+ cations undergo prompt C–Br bond fission to form predominantly C2H5+ + Br* products with a near-limiting ‘parallel’ recoil velocity distribution. The observed C2H3+ + H2 + Br product channel is thought to arise via unimolecular decay of highly internally excited C2H5+ products formed following radiationless transfer from the initial excited state populated by photon absorption. Broadly similar behaviour is observed in the case of C2H5I+, along with an additional energetically accessible C–I bond fission channel to form C2H5 + I+ products. HX (X = Br, I) elimination from the highly internally excited C2H5X+ cation is deemed the most probable route to forming the C2H4+ fragment ions observed from both cations. Finally, both ethyl halide cations also show evidence of a minor C–C bond fission process to form CH2X+ + CH3 products

Photofragmentation dynamics of N,N-dimethylformamide following excitation at 193 nm

N,N-dimethylformamide, HCON(CH3)2, is a useful model compound for investigating peptide bond photofragmentation dynamics. We report data from a comprehensive experimental and theoretical study into the photofragmentation dynamics of N,N-dimethylformamide in the gas phase at 193 nm. Through a combination of velocity-map imaging and hydrogen atom Rydberg tagging photofragment translational spectroscopy, we have identified two primary fragmentation channels, namely fission of the NCO `peptide' bond, and NCH3 bond fission leading to loss of CH3. The possible fragmentation channels leading to the observed products are rationalised with recourse to CASPT2 calculations of the ground and first few excited-state potential energy curves along the relevant dissociation coordinates, and the results are compared with data from previous experimental and theoretical studies on the same system

Towards the complete experiment: Measurement of s((1)d(2)) polarization in correlation with single rotational states of co(j) from the photodissociation of oriented ocs(v(2)=1 vertical bar jlm=111)

Contains fulltext : 92507.pdf (publisher's version ) (Open Access

High-resolution slice imaging of quantum state-to-state photodissociation of methyl bromide

The photodissociation of rotationally state-selected methyl bromide is studied in the wavelength region between 213 and 235 nm using slice imaging. A hexapole state selector is used to focus a single (JK=11) rotational quantum state of the parent molecule, and a high speed slice imaging detector measures directly the three-dimensional recoil distribution of the methyl fragment. Experiments were performed on both normal (C H3 Br) and deuterated (C D3 Br) parent molecules. The velocity distribution of the methyl fragment shows a rich structure, especially for the C D3 photofragment, assigned to the formation of vibrationally excited methyl fragments in the 1 and 4 vibrational modes. The C H3 fragment formed with ground state Br (P 32 2) is observed to be rotationally more excited, by some 230-340 cm-1, compared to the methyl fragment formed with spin-orbit excited Br (P 12 2). Branching ratios and angular distributions are obtained for various methyl product states and they are observed to vary with photodissociation energy. The nonadiabatic transition probability for the Q 0+ 3 → Q11 transition is calculated from the images and differences between the isotopes are observed. Comparison with previous non-state-selected experiments indicates an enhanced nonadiabatic transition probability for state-selected K=1 methyl bromide parent molecules. From the state-to-state photodissociation experiments the dissociationenergy for both isotopes was determined, D0 (C H3 Br) =23 400±133 cm-1 and D0 (C D3 Br) =23 827±94 cm-1. © 2007 American Institute of Physics

Slice imaging of quantum state-to-state photodissociation dynamics of OCS

Slice imaging experiments are reported for the quantum state-to-state photodissociation dynamics of OCS. Both one-laser and two-laser experiments are presented detecting CO(J) or S

High resolution slice imaging of a molecular speed distribution

High resolution slice imaging experiments are reported measuring the speed distribution of molecular fragments, recoiling at a most probable speed