Effects of surface charge density and distribution on the
... peak of Na+ , on the contrary, is only marginally low. Moreover, orientational polarization of water molecules close to the channel wall can be deduced from the concentration profiles of H and O atoms in Figure 3. Because the first concentration peak of H atoms is closer to the wall than the first p ...
... peak of Na+ , on the contrary, is only marginally low. Moreover, orientational polarization of water molecules close to the channel wall can be deduced from the concentration profiles of H and O atoms in Figure 3. Because the first concentration peak of H atoms is closer to the wall than the first p ...
www.rsc.org/nanoscale Volume 5 | Number 16 | 21 August 2013
... lateral relaxation.4 Such a limitation in lattice-mismatched systems originates from the prerequisite that epitaxial crystalline overlayer (epilayer) materials form covalent bonding with the substrate. However, it is also possible that only a weak van der Waals interaction exists at the epilayer–sub ...
... lateral relaxation.4 Such a limitation in lattice-mismatched systems originates from the prerequisite that epitaxial crystalline overlayer (epilayer) materials form covalent bonding with the substrate. However, it is also possible that only a weak van der Waals interaction exists at the epilayer–sub ...
Materials - Hodder Education
... History has characterized civilizations by the materials they used: Stone Age, Bronze Age, Iron Age and now the Plastics or Polymer Age and perhaps later the Nano-materials Age. The use of materials, especially alloys, was developed based on observations and measurement of their chemical and physica ...
... History has characterized civilizations by the materials they used: Stone Age, Bronze Age, Iron Age and now the Plastics or Polymer Age and perhaps later the Nano-materials Age. The use of materials, especially alloys, was developed based on observations and measurement of their chemical and physica ...
Name: Period:______ Let`s make some sandwiches! Introduction: If
... Name:______________________ Period:_________ Let’s make some sandwiches! Introduction: If a sandwich shop runs out of bread, the shop closes down. No more sandwiches can be fully made without ordering more bread from a bakery. A similar thing happens in a chemical reaction. If there are fixed amount ...
... Name:______________________ Period:_________ Let’s make some sandwiches! Introduction: If a sandwich shop runs out of bread, the shop closes down. No more sandwiches can be fully made without ordering more bread from a bakery. A similar thing happens in a chemical reaction. If there are fixed amount ...
Full text
... charge distribution of the electrons in the other wave functions. In such a treatment, the field of the average electron distribution derived from the wave functions φ1, φ2, Ö φn must be the same as the field used in evaluating these wave functions. This aspect has led to the term ëself-consistent f ...
... charge distribution of the electrons in the other wave functions. In such a treatment, the field of the average electron distribution derived from the wave functions φ1, φ2, Ö φn must be the same as the field used in evaluating these wave functions. This aspect has led to the term ëself-consistent f ...
Computational Chemistry Methods for Nanoporous Materials
... Finally, we note that a simple and useful way to supervise DFT calculations is to examine, during the self-consistent field (SCF) iteration scheme for the calculation of the density and energy, the atomic partial charges (calculated by the software with the Mulliken scheme). Because we have a reasona ...
... Finally, we note that a simple and useful way to supervise DFT calculations is to examine, during the self-consistent field (SCF) iteration scheme for the calculation of the density and energy, the atomic partial charges (calculated by the software with the Mulliken scheme). Because we have a reasona ...
Self-assembled monolayer
Self-assembled monolayers (SAM) of organic molecules are molecular assemblies formed spontaneously on surfaces by adsorption and are organized into more or less large ordered domains. In some cases molecules that form the monolayer do not interact strongly with the substrate. This is the case for instance of the two-dimensional supramolecular networks of e.g. Perylene-tetracarboxylicacid-dianhydride (PTCDA) on gold or of e.g. porphyrins on highly oriented pyrolitic graphite (HOPG). In other cases the molecules possess a head group that has a strong affinity to the substrate and anchors the molecule to it. Such a SAM consisting of a head group, tail and functional end group is depicted in Figure 1. Common head groups include thiols, silanes, phosphonates, etc.SAMs are created by the chemisorption of ""head groups"" onto a substrate from either the vapor or liquid phase followed by a slow organization of ""tail groups"". Initially, at small molecular density on the surface, adsorbate molecules form either a disordered mass of molecules or form an ordered two-dimensional ""lying down phase"", and at higher molecular coverage, over a period of minutes to hours, begin to form three-dimensional crystalline or semicrystalline structures on the substrate surface. The ""head groups"" assemble together on the substrate, while the tail groups assemble far from the substrate. Areas of close-packed molecules nucleate and grow until the surface of the substrate is covered in a single monolayer.Adsorbate molecules adsorb readily because they lower the surface free-energy of the substrate and are stable due to the strong chemisorption of the ""head groups."" These bonds create monolayers that are more stable than the physisorbed bonds of Langmuir–Blodgett films. A Trichlorosilane based ""head group"", for example in a FDTS molecule reacts with an hydroxyl group on a substrate, and forms very stable, covalent bond [R-Si-O-substrate] with an energy of 452 kJ/mol. Thiol-metal bonds, that are on the order of 100 kJ/mol, making the bond a fairly stable in a variety of temperature, solvents, and potentials. The monolayer packs tightly due to van der Waals interactions, thereby reducing its own free energy. The adsorption can be described by the Langmuir adsorption isotherm if lateral interactions are neglected. If they cannot be neglected, the adsorption is better described by the Frumkin isotherm.