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Full-Text Articles in Physical Sciences and Mathematics
Quantitative Force Measurements In Liquid Using Frequency Modulation Atomic Force Microscopy, Suzi P. Jarvis, S. Akita, Takayuki Uchihashi, John E. Sader, Y. Nakayama, Michael J. Higgins, S Yasuda
Quantitative Force Measurements In Liquid Using Frequency Modulation Atomic Force Microscopy, Suzi P. Jarvis, S. Akita, Takayuki Uchihashi, John E. Sader, Y. Nakayama, Michael J. Higgins, S Yasuda
Faculty of Science - Papers (Archive)
The measurement of short-range forces with the atomic force microscope (AFM) typically requires implementation of dynamic techniques to maintain sensitivity and stability. While frequency modulation atomic force microscopy (FM-AFM) is used widely for high-resolution imaging and quantitative force measurements in vacuum, quantitative force measurements using FM-AFM in liquids have proven elusive. Here we demonstrate that the formalism derived for operation in vacuum can also be used in liquids, provided certain modifications are implemented. To facilitate comparison with previous measurements taken using surface forces apparatus, we choose a model system (octamethylcyclotetrasiloxane) that is known to exhibit short-ranged structural ordering when confined …
Charge-On-Spring Polarizable Water Models Revisited: From Water Clusters To Liquid Water To Ice, Haibo Yu, Wilfred Van Gunsteren
Charge-On-Spring Polarizable Water Models Revisited: From Water Clusters To Liquid Water To Ice, Haibo Yu, Wilfred Van Gunsteren
Faculty of Science - Papers (Archive)
The properties of two improved versions of charge-on-spring �COS� polarizable water models (COS/G2 and COS/G3) that explicitly include nonadditive polarization effects are reported. In COS models, the polarization is represented via a self-consistently induced dipole moment consisting of a pair of separated charges. A previous polarizable water model (COS/B2), upon which the improved versions are based, was developed by Yu, Hansson, and van Gunsteren �J. Chem. Phys. 118, 221 �2003��. To improve the COS/B2 model, which overestimated the dielectric permittivity, one additional virtual atomic site was used to reproduce the water monomer quadrupole moments besides the water monomer dipole moment …