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The C 60 molecule has been recently detected in a wide range of astrophysical environments through its four active intramolecular vibrational modes (T 1u ) near 18.9 µm, 17.4 µm, 8.5 µm, and 7.0 µm. The strengths of the mid-infrared emission bands have been used to infer astrophysical conditions in the fullerene-rich regions. Widely varying values of the relative intrinsic strengths (RIS) of these four bands are reported in laboratory and theoretical papers, which impedes the derivation of the excitation mechanism of C 60 in the astrophysical sources. The spectroscopic analysis of the C 60 samples produced with our method delivers highly reproducible RIS values of 100, 25 ± 1, 26 ± 1 and 40 ± 4. A comparison of the inferred C 60 emission band strengths with the astrophysical data shows that the observed strengths cannot be explained in terms of fluorescent or thermal emission alone. The large range in the observed 17.4 µm/18.9 µm emission ratios indicates that either the emission bands contain significant contributions from emitters other than C 60 , or that the population distribution among the C 60 vibrational modes is affected by physical processes other than thermal or UV excitation, such as chemo-luminescence from nascent C 60 or possibly, Poincaré fluorescence resulting from an inverse internal energy conversion. We have carefully analyzed the effect of the weakly-active fundamental modes and second order modes in the mid-infrared spectrum of C 60 and propose that neutral C 60 is the carrier of the unidentified emission band at 6.49 µm which has been observed in fullerene-rich environments.

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Vacuum-Ultraviolet (VUV) radiation is responsible for the photo-processing of simple and complex molecules in several terrestrial and extraterrestrial environments. In the laboratory such radiation is commonly simulated by inexpensive and easy-to-use microwave-powered hydrogen discharge lamps. However, VUV flux measurements are not trivial and the methods/devices typically used for this purpose, mainly actinometry and calibrated VUV silicon photodiodes, are not very accurate or expensive and lack of general suitability to experimental setups. Here, we present a straightforward method for measuring the VUV photon flux based on the photoelectric effect and using a gold photodetector. This method is easily applicable to most experimental setups, bypasses the major problems of the other methods, and provides reliable flux measurements. As a case study, the method is applied to a microwave-powered hydrogen discharge lamp. In addition, the comparison of these flux measurements to those obtained by O2 actinometry experiments allow us to estimate the quantum yield (QY) values QY122 = 0.44 ± 0.16 and QY160 = 0.87 ± 0.30 for solid-phase O2 actinometry.

We review the currently known methods of producing gold nitride and report on the influence of electrically isolated substrates on the growth of gold nitride films by reactive ion sputtering (RIS). It is found that isolation of the substrate decreases grain size and increases nitrogen content, the latter attributed to longer nitrogen ion lifetime on the surface of the growing film. The chemical reactivity of gold nitride is compared with that of pure gold films using the adsorption of 1-dodecyl mercaptan (CH 3 (CH 2 ) 11 SH) as a model system and it is found that there is no significant difference between gold films and gold nitride in terms of Au-S binding. However, gold nitride nanoparticles are suggested to be worthy of further investigation in terms of their catalytic properties.

Post-deposition molecular rearrangement in thin organic films is revealed by in situ real-time photoelectron spectroscopy during organic molecular beam deposition. Agreement between real time spectroscopy and Monte Carlo modeling confirms the role of nearest-neighbor molecular attraction in driving a time-dependent morphology for oriented films of tin phthalocyanine (SnPc) on a range of substrates. The time-dependent molecular self-organization occurs over timescales comparable to the growth rates and is therefore an important factor in the degradation of thin films of organic semiconductors typically considered for the fabrication of multilayer semiconductor devices. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775762]publishersversionPeer reviewe

The structure of nitride containing gold films produced by reactive ion sputtering and nitrogen plasma etching is investigated using x-ray photoelectron spectroscopy and x-ray diffraction. It is found that gold nitride is a solid solution of nitrogen atoms dissolved in a fcc gold matrix. Differences between the strain and lattice parameters of gold and gold nitride films were observed and are explained by interstitial nitrogen present in the latter. c 2008 American Institute of Physics. [DOI: 10.1063/1.3040717]\u

The nitration of gold surfaces is a nonpolluting method, which can lead to large scale production of substrates with remarkable properties and applications. We present a topographical study of the nanoscale structure of the gold nitride surfaces produced by radio frequency ͑rf͒ nitrogen plasma etching of thin gold films. Atomic force microscopy images taken after rf etching reveal the striking appearance of the cluster assembly with large clusters surrounded by small clusters ͑7.9Ϯ 1.4 and 2.3Ϯ 0.9 nm, respectively͒ appearing to exhibit an attractive interaction. We discuss the possible mechanism for this attraction based on a colloid model by Messina et al. ͓Phys. Rev. Lett. 85, 872 ͑2000͔͒. This surface exhibits a notable surface enhanced Raman scattering effect demonstrated with L-alanine and rhodamine-6G. The significance of this work is that we found that this SERS active gold nitride surface can be prepared in just one step: by nitrogen plasma etching a thin gold film. Until now most SERS active gold cluster covered surfaces have been prepared in several steps very often requiring complex lithography.