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Volume 126, Issue 22, 14 June 2007
126(2007); http://dx.doi.org/10.1063/1.2745718View Description Hide Description
Initial simulated values of the surface tension for the SPC/E water model have indicated excellent agreement with experiment. More recently, differing values have been obtained which are significantly lower than previous estimates. Here, we attempt to explain the differences between the previous studies and show that a variety of simulation conditions can affect the final surface tension values. Consistent values for the surface tensions of six common fixed charge water models (TIP3P, SPC, SPC/E, TIP4P, TIP5P, and TIP6P) are then determined for four temperatures between 275 and . The SPC/E and TIP6P models provide the best agreement with experiment.
126(2007); http://dx.doi.org/10.1063/1.2748747View Description Hide Description
Photon-trap spectroscopy, a generalized scheme of cavity ringdown spectroscopy, is applied to measure an infrared spectrum of the C–H stretching vibration of alkylsiloxane monolayer films grafted on a silicon substrate. A continuous-wave laser beam is introduced into a high-finesse Fabry-Pérot cavity containing the substrate placed exactly normal to the light beam to minimize optical losses. The lifetime of the light trapped in the cavity is measured to detect optical absorption sensitively. The results show clear dependence of the absorbance on the location of the monolayers with respect to a standing wave formed in the cavity; the absorbance is practically zero when the monolayers on both the surfaces are adjusted at nodes, whereas it is maximized at antinodes. The present experiment is materialized on the basis of the principles established by our previous study [Terasaki et al., J. Opt. Soc. Am. B22, 675 (2005)].