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The application of a novel UV fs Laser Ablation Ionization Mass Spectrometry approach for chemical depth profiling of low-melting point, high surface roughness SnAg solder bump features is presented. The obtained submicrometer resolved three-dimensional compositional data reveal unprecedented information on the distribution of individual elements inside the solder bump matrix. Moreover, the determination of matrix-matched relative sensitivity coefficients allows the first report on quantitative assessment of the SnAg alloy composition. These results significantly contribute to an in-depth understanding of the SnAg plating process. This experimental procedure may find application in future additive performance screening.

We demonstrate the feasibility of the time-delayed femtosecond CARS (fs-CARS) technique in a dense gas environment. The experiments were performed on N2 molecules between 0.2 and 5 bar pressure. The method provides several advantages compared with its wavenumber-resolved counterpart, e.g. the possible separation of the non-resonant contributions to the signal, and is more suitable when the isolated lines approximations collapse and complex line mixing and energy transfer models have to be implemented in the signal description. The experimental results are in good agreement with theoretical considerations based on collision-induced rotational energy transfer (RET) models such as the common energy-corrected sudden approximation (ECS). Moreover, it is shown that the structure of the time-delayed signals is very sensitive to the applied pressures. Therefore, fs-CARS is an ideal supplementary tool for investigations of collision-induced spectroscopic effects, which are decisive for temperature and concentration determination in combustion processes. Copyright © 2002 John Wiley & Sons, Ltd.

The laser-induced fluorescence (LIF) excitation spectrum of jet-cooled 2, 6-dicyano-3,5-dimethylaniline (DCDMA) has been measured in the spectral range of 29,750–32,250cm−1. The band origin at 29,860.8 cm−1and as many as 250 vibrational bands have been identified in the excitation spectrum. The analysis of the excitation spectrum of DCDMA gives more than 28 vibrational modes involving aromatic ring oscillations and oscillations related to the substituent groups. DCDMA is nonplanar in the ground state, with the NH2plane at about 9° with respect to the molecular plane (RHF/6-31G*). The singlet excited molecule is planar (CIS/6-31G*). Both CIS/6-31G* and CASPT2 calculations predict that the lowest excited state of DCDMA involves a dominant HOMO-LUMO excited configuration. The characteristic feature of the excitation spectrum of DCDMA is the presence of progressions in the low-frequency mode, 112 cm−1. The calculations suggest that this mode and some other active modes involve motions of the amino group and strongly interacting adjacent cyano substituents.

The electronic absorption spectra of the monohydrogenated odd carbon chain anions C2n-1H^- (n = 5−8) have been measured in the gas phase using resonant two-color electron detachment spectroscopy. As for the even series C2nH^- (n = 5−10) electronic transitions of two isomeric species are observed. Ab initio calculations on C9H^- support the assignment of one band system to a ³Σ^- ← X³Σ^- transition of a linear molecule and the other to a ¹A‘ ← X¹A‘ transition of a bent isomer. The wavelength of the band systems shows an approximately linear dependence on the chain length. This plot is offset by 60 nm compared to the one for the linear C2nH^- anions, while the wavelengths for the even and odd carbon series of the cumulene-like isomer fall on the same line. These trends can be rationalized in terms of their electronic structure.

Context.The small radius and high density of CoRoT-7b implies that this transiting planet belongs to a different species than all transiting planets previously found. Current models suggest that this is the first transiting rocky planet found outside the solar system. Given that the planet orbits a solar-like star at a distance of only 4.5 R∗, it is expected that material released from its surface may then form an exosphere.