Isobutyl acetate: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations

The high-resolution vacuum ultraviolet photoabsorption spectrum of isobutyl acetate, C6H12O2, is presented here and was measured over the energy range 4.3–10.8 eV (290–115 nm). Valence and Rydberg transitions with their associated vibronic series have been observed in the photoabsorption spectrum and are assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. The measured photoabsorption cross sections have been used to calculate the photolysis lifetime of this ester in the Earth’s upper atmosphere (20–50 km). Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of isobutyl acetate and are compared with a photoelectron spectrum (from 9.5 to 16.7 eV), recorded for the first time. Vibrational structure is observed in the first photoelectron band of this molecule

Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations

The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0-275.5 nm (10.75-4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of ethyl formate and are compared with a newly recorded He(I) photoelectron spectrum (from 10.1 to 16.1 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross sections have been used to calculate the photolysis lifetime of ethyl formate in the upper stratosphere (20-50 km)

Electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations of ethyl acetate

Abstract: The high-resolution vacuum ultraviolet photoabsorption spectrum of ethyl acetate,C4H8O2, is presented over the energy range 4.5−10.7 eV (275.5−116.0 nm). Valence and Rydberg transitionsand their associated vibronic series observed in the photoabsorption spectrum, have beenassigned in accordance with new ab initio calculations of the vertical excitation energiesand oscillator strengths. Also, the photoabsorption cross sections have been used tocalculate the photolysis lifetime of this ester in the upper stratosphere(20−50 km). Calculationshave also been carried out to determine the ionisation energies and fine structure of thelowest ionic state of ethyl acetate and are compared with a newly recorded photoelectronspectrum (from 9.5 to 16.7 eV). Vibrational structure is observed in the firstphotoelectron band of this molecule for the first time

Roadmap on dynamics of molecules and clusters in the gas phase

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Sheet piling as an alternative to diaphragm walls on the underground passage site along the railway line Warsaw-Lublin

Nowoczesne budownictwo umożliwia wykonywanie konstrukcji w sposób dostoswany do wymagań budowy. W związku z tym często spotykamy się ze zmianą technologii wykonywania robót. Tak też było na budowie przejścia podziemnego P1 realizowanego w ramach przebudowy ulic Żegańskiej i Zwoleńskiej w Warszawie pod linia kolejową nr 007 relacji Warszawa Dorhusk, gdzie ściany szczelinowe zostały zastąpione grodzicami stalowymi i konstrukcją żelbetowa monolityczną. Takie rozwiązanie wynikało z konieczności etapowania robót wynikających z dostępnych zamknięć kolejowych.The modern construction methodology allows to change the designed technology to the more appropriate for the building site. This approach was applied on the tunnel passage erected as a part of the Żegańska and Zwoleńska street refurbishment in Warsaw, Poland. Due to the either railway lines tracks closers or to the construction stages it was necessary to change the diaphragm walls to the sheet piles technology. The whole construction was redesign to the monolith reinforcement concrete

Theoretical study of the photoelectron spectrum of ethyl formate:

The first ionization energy and associated photoelectron spectrum of ethyl formate are investigated with quantum chemistry calculations. The geometries, harmonic vibrational frequencies and first ionization energy are computed at the Hartree-Fock (HF) and at the second order Møller-Plesset perturbation theory (MP2). Moreover, accurate ionization energies are obtained with the Coupled-Cluster theory including singles and doubles excitations (CCSD) as well as singles, doubles and perturbative triples excitations (CCSD(T)). Then, these ab initio results are assessed with respect to experimental values. Additionally, the ionization energies are also calculated with the computationally attractive density functional theory (DFT). In this case the accuracy of several exchange-correlation functionals is evaluated by comparison with the ab initio and experimental results. In a next step, the vibrational structure of the photoelectron spectrum is simulated at the HF, MP2 and DFT levels via the calculation of the Franck-Condon factors. These simulations are compared to the experimental photoelectron spectrum and allow an accurate reproduction of the vibrational progression

A new method to estimate dimensions of vehicle using a single camera

The capability of a telematic vision system of estimating dimensions of vehicles is used for such tasks as vehicle classification or preselection of vehicles that violate local vehicle size limitations. Also in some European countries dimensions of heavy vehicles must obey some global regulations. Furthermore, vehicle size estimation allows us to determine the structure of traffic and can be very useful for advanced traffic flow control. Many existing Intelligent Transportation Systems consist of a large number of video cameras located in various places e.g., the ITS in Wrocław uses more than 1400 cameras. In this paper we propose a new method developed by the ArsNumerica Group and CyberTech Scientific Circle for the precise estimation of vehicle sizes using a single camera. The method does not require the entering of measurements such as the distance between lane lines or the height of the camera above the roadway. Only one vehicle’s dimensions are used for calibration. The proposed method is easy to implement and may be applied with the OpenCV library which is free both for academic and commercial use. The method is tested on real-world video streams. The obtained results are shown and analyzed in the paper

Valence and Ionic Lowest-Lying Electronic States of Isobutyl Formate Studied by High-Resolution Vacuum Ultraviolet Photoabsorption, Photoelectron Spectroscopy, and Ab Initio Calculations

The highest resolution vacuum ultraviolet photoabsorption spectrum of isobutyl formate, C5H10O2, yet reported is presented over the energy range 4.5-10.7 eV (275.5-118.0 nm) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of isobutyl formate and are compared with a newly recorded photoelectron spectrum (from 9.0 to 27.0 eV). The value of the first ionization energy was determined to be 10.508 eV (adiabatic) and 10.837 eV (vertical). New vibrational structure is observed in the first photoelectron band, predominantly resulting from C-O and Ci=O stretches of the molecule. The photoabsorption cross sections have been used to calculate the photolysis lifetime of isobutyl formate in the upper stratosphere (20-50 km), indicating that the hydroxyl radical processes will be the main loss process for isobutyl formate

Determination of energy-transfer distributions in ionizing ion-molecule collisions

International audienceSynopsis The main objective of this study is to determine the energy transfer occuring in ion-molecule collisions. In order to solve this problem, we followed two approaches; the first one by validating a purely experimental method and the second one by testing a new theoretical model M 3 C (Microcanonical Metropolis Monte Carlo)