Atomistic simulations of organic thin film deposition through hyperthermal cluster impactsAn intense, continuous beam of metal clusters and cluster ions is produced by combining a magnetron sputter discharge with a gas aggregation source. The average cluster size can be varied between 50 and more than 10 6 atoms per cluster. The sputter discharge is also used to ionize the clusters; between 30% and 80% of them carry a charge without further electron-impact ionization. Mo n -clusters with n:;::::, 1200 were separated from the neutral clusters, accelerated, and deposited on a polished Cu substrate. Above a kinetic energy of 6 keY, highly reflecting, strongly adhering thin films are formed on room-temperature substrates. The films can be mechanically polished, which increases the reflectivity from 95% to 97% at 10.6 /-Lm. Rutherford backscattering spectroscopy data reveal that less than 0.5% argon is incorporated into the films. The standard structure zone model of Movchan, Demchishin, and Thornton [in B. Chapman, Glow Discharge Processes. (Wiley, New York, 1982)] is not applicable. The impact of an energetic cluster leads locally to a sudden increase of pressure and temperature. A tiny, high-temperature spot is formed at each impact of an energetic cluster. The high local temperature present for several picoseconds leads to the observed film properties. The main advantage of the method seems to be that excellent thin films can be produced on room-temperature substrates. The name "energetic cluster impact" is proposed for this new deposition method.3266

A completely ionized and clustered beam of Mo or Cu is deposited with variable kinetic energy on a substrate, and the filling of micron-sized contact holes on semiconductor devices is studied. An excellent hole filling is obtained for the impact of charged copper clusters, if they contain 1000–3000 Cu atoms and impinge with a kinetic energy of about 10 eV per atom on a substrate having a temperature of 500 K. The morphology of small hole fillings by slow and energetic cluster impact is discussed.

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We present results for the measurement of φ meson production via its charged kaon decay channel φ → K + K − in Au + Au collisions at √ s NN = 62.4, 130, and 200 GeV, and in p + p and d + Au collisions at √ s NN = 200 GeV from the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC). The midrapidity (|y| < 0.5) φ meson transverse momentum (p T ) spectra in central Au + Au collisions are found to be well described by a single exponential distribution. On the other hand, the p T spectra from p + p, d + Au, and peripheral Au + Au collisions show power-law tails at intermediate and high p T and are described better by Levy distributions. The constant φ/K − yield ratio vs beam species, collision centrality, and colliding energy is in contradiction with expectations from models having kaon coalescence as the dominant mechanism for φ production at RHIC. The /φ yield ratio as a function of p T is consistent with a model based on the recombination of thermal s quarks up to p T ∼ 4 GeV/c, but disagrees at higher transverse momenta. The measured nuclear modification factor, R dAu , for the φ meson increases above unity at intermediate p T , similar to that for pions and protons, while R AA is suppressed due to the energy loss effect in central Au + Au collisions. Number of constituent quark scaling of both R cp and v 2 for the φ meson with respect to other hadrons in Au + Au collisions 064903-2

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