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The adiabatic core-shell model by Mitchell and Fincham is a simple method for adding polarizabilityto a system. In order to mimic the electron shell of an ion, asatellite particle is attached to it. This way the ions are split intoa core and a shell where the latter is meant to react to theelectrostatic environment inducing polarizability. See the Howto polarizable doc page for a discussion of allthe polarizable models available in LAMMPS.

• Core Shell Technologies
• Core Shell Nanoparticles

Technically, shells are attached to the cores by a spring force f =k*r where k is a parameterized spring constant and r is the distancebetween the core and the shell. The charges of the core and the shelladd up to the ion charge, thus q(ion) = q(core) + q(shell). Thissetup introduces the ion polarizability (alpha) given byalpha = q(shell)^2 / k. In asimilar fashion the mass of the ion is distributed on the core and theshell with the core having the larger mass.

To run this model in LAMMPS, atom_stylefull canbe used since atom charge and bonds are needed. Each kind ofcore/shell pair requires two atom types and a bond type. The core andshell of a core/shell pair should be bonded to each other with aharmonic bond that provides the spring force. For example, a data filefor NaCl, as found in examples/coreshell, has this format:

Non-Coulombic (e.g. Lennard-Jones) pairwise interactions are onlydefined between the shells. Coulombic interactions are definedbetween all cores and shells. If desired, additional bonds can bespecified between cores.

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The special_bonds command should be used toturn-off the Coulombic interaction within core/shell pairs, since thatinteraction is set by the bond spring. This is done using thespecial_bonds command with a 1-2 weight = 0.0,which is the default value. It needs to be considered whether one hasto adjust the special_bonds weighting accordingto the molecular topology since the interactions of the shells arebypassed over an extra bond.

Filter Drier Cores and Blocks by Emerson Flow Controls and Parker Haniffin can be found here. There is an replacement core for every application, and many cores are completely interchangeable with other cores and shells. Core-shell particles and high separation efficiency. Core-shell particles’ high separation efficiency is largely due to more rapid analyte mass transfer – from the mobile phase through to the stationary phase and back again. This is because diffusion only occurs via the porous, outer layer of the particle rather than the entire particle. In this work, we demonstrate that the strong synergy between Cu core and ultrathin lead (Pb) shell (0.7 nm) in the Cu/Pb core/shell nanocrystals (NCs, CuPb-0.7/C) significantly boosts the electrocatalytic reduction of CO 2 toward C 2+ products (products with at least two carbon atoms).

Note that this core/shell implementation does not require all ions tobe polarized. One can mix core/shell pairs and ions without asatellite particle if desired.

Since the core/shell model permits distances of r = 0.0 between thecore and shell, a pair style with a “cs” suffix needs to be used toimplement a valid long-range Coulombic correction. Several such pairstyles are provided in the CORESHELL package. See this doc page for details. All of the core/shell enabled pairstyles require the use of a long-range Coulombic solver, as specifiedby the kspace_style command. Either the PPPM orEwald solvers can be used.

For the NaCL example problem, these pair style and bond style settingsare used:

When running dynamics with the adiabatic core/shell model, thefollowing issues should be considered. The relative motion ofthe core and shell particles corresponds to the polarization,hereby an instantaneous relaxation of the shells is approximatedand a fast core/shell spring frequency ensures a nearly constantinternal kinetic energy during the simulation.Thermostats can alter this polarization behavior, by scaling theinternal kinetic energy, meaning the shell will not react freely toits electrostatic environment.Therefore it is typically desirable to decouple the relative motion ofthe core/shell pair, which is an imaginary degree of freedom, from thereal physical system. To do that, the compute temp/cs command can be used, in conjunction withany of the thermostat fixes, such as fix nvt or fix langevin. This compute uses the center-of-mass velocityof the core/shell pairs to calculate a temperature, and insures thatvelocity is what is rescaled for thermostatting purposes. Thiscompute also works for a system with both core/shell pairs andnon-polarized ions (ions without an attached satellite particle). Thecompute temp/cs command requires input of twogroups, one for the core atoms, another for the shell atoms.Non-polarized ions which might also be included in the treated systemshould not be included into either of these groups, they are takeninto account by the group-ID (second argument) of the compute. Thegroups can be defined using the group *type* command.Note that to perform thermostatting using this definition oftemperature, the fix modify temp command should beused to assign the compute to the thermostat fix. Likewise thethermo_modify temp command can be used to makethis temperature be output for the overall system.

For the NaCl example, this can be done as follows:

The pressure for the core/shell system is computed via the regularLAMMPS convention by treating the cores and shells as individual particles. For the thermo output of the pressureas well as for the application of a barostat, it is necessary touse an additional pressure compute based onthe default temperature and specifying it as asecond argument in fix modify andthermo_modify resulting in:

If compute temp/cs is used, the decoupledrelative motion of the core and the shell should in theory bestable. However numerical fluctuation can introduce a smallmomentum to the system, which is noticeable over long trajectories.Therefore it is recommendable to use the fix momentum command in combination with compute temp/cs when equilibrating the system toprevent any drift.

When initializing the velocities of a system with core/shell pairs, itis also desirable to not introduce energy into the relative motion ofthe core/shell particles, but only assign a center-of-mass velocity tothe pairs. This can be done by using the bias keyword of thevelocity create command and assigning the compute temp/cs command to the temp keyword of thevelocity command, e.g.

To maintain the correct polarizability of the core/shell pairs, thekinetic energy of the internal motion shall remain nearly constant.Therefore the choice of spring force and mass ratio need to ensuremuch faster relative motion of the 2 atoms within the core/shell pairthan their center-of-mass velocity. This allows the shells toeffectively react instantaneously to the electrostatic environment andlimits energy transfer to or from the core/shell oscillators.This fast movement also dictates the timestep that can be used.

The primary literature of the adiabatic core/shell model suggests thatthe fast relative motion of the core/shell pairs only allows negligibleenergy transfer to the environment.The mentioned energy transfer will typically lead to a small driftin total energy over time. This internal energy can be monitoredusing the compute chunk/atom and compute temp/chunk commands. The internal kineticenergies of each core/shell pair can then be summed using the sum()special function of the variable command. Or they canbe time/averaged and output using the fix ave/timecommand. To use these commands, each core/shell pair must be definedas a “chunk”. If each core/shell pair is defined as its own molecule,the molecule ID can be used to define the chunks. If cores are bondedto each other to form larger molecules, the chunks can be identifiedby the fix property/atom via assigning acore/shell ID to each atom using a special field in the data file readby the read_data command. This field can then beaccessed by the compute property/atomcommand, to use as input to the compute chunk/atom command to define the core/shellpairs as chunks.

For example if core/shell pairs are the only molecules:

For example if core/shell pairs and other molecules are present:

The additional section in the date file would be formatted like this:

(Mitchell and Fincham) Mitchell, Fincham, J Phys Condensed Matter,5, 1031-1038 (1993).

(Fincham) Fincham, Mackrodt and Mitchell, J Phys Condensed Matter,6, 393-404 (1994).

There are multiple ways to install PowerShell in Windows.

Prerequisites

The latest release of PowerShell is supported on Windows 7 SP1, Server 2008 R2, and later versions.

To enable PowerShell remoting over WSMan, the following prerequisites need to be met:

• Install the Universal C Runtime onWindows versions predating Windows 10. It's available via direct download or Windows Update. Fullypatched systems already have this package installed.
• Install the Windows Management Framework (WMF) 4.0 or newer on Windows 7 and Windows Server 2008R2. For more information about WMF, see WMF Overview.

Download the installer package

To install PowerShell on Windows, download the latest install package from GitHub. You can alsofind the latest preview version. Scroll down to the Assets section of the Release page. TheAssets section may be collapsed, so you may need to click to expand it.

Installing the MSI package

The MSI file looks like PowerShell-<version>-win-<os-arch>.msi. For example:

• PowerShell-7.1.3-win-x64.msi
• PowerShell-7.1.3-win-x86.msi

Once downloaded, double-click the installer and follow the prompts.

The installer creates a shortcut in the Windows Start Menu.

• By default the package is installed to $env:ProgramFilesPowerShell<version>
• You can launch PowerShell via the Start Menu or $env:ProgramFilesPowerShell<version>pwsh.exe

Note

PowerShell 7.1 installs to a new directory and runs side-by-side with Windows PowerShell 5.1.PowerShell 7.1 is an in-place upgrade that replaces PowerShell 6.x. or PowerShell 7.0.

• PowerShell 7.1 is installed to $env:ProgramFilesPowerShell7
• The $env:ProgramFilesPowerShell7 folder is added to $env:PATH
• The $env:ProgramFilesPowerShell6 folder is deleted

If you need to run PowerShell 7.1 side-by-side with other versions, use the ZIP installmethod to install the other version to a different folder.

Administrative install from the command line

MSI packages can be installed from the command line allowing administrators to deploy packageswithout user interaction. The MSI package includes the following properties to control theinstallation options:

• ADD_EXPLORER_CONTEXT_MENU_OPENPOWERSHELL - This property controls the option for adding theOpen PowerShell item to the context menu in Windows Explorer.
• ADD_FILE_CONTEXT_MENU_RUNPOWERSHELL - This property controls the option for adding theRun with PowerShell item to the context menu in Windows Explorer.
• ENABLE_PSREMOTING - This property controls the option for enabling PowerShell remoting duringinstallation.
• REGISTER_MANIFEST - This property controls the option for registering the Windows EventLogging manifest.

The following example shows how to silently install PowerShell with all the install options enabled.

For a full list of command-line options for Msiexec.exe, seeCommand line options.

Registry keys created during installation

Beginning in PowerShell 7.1, the MSI package creates registry keys that store the installationlocation and version of PowerShell. These values are located inHKLMSoftwareMicrosoftPowerShellCoreInstalledVersions<GUID>. The value of<GUID> is unique for each build type (release or preview), major version, and architecture.

This can be used by administrators and developers to find the path to PowerShell. The <GUID>values will be the same for all preview and minor version releases. The <GUID>values are changed for each major release.

Installing the ZIP package

PowerShell binary ZIP archives are provided to enable advanced deployment scenarios. Download one ofthe following ZIP archives from the [releases][releases] page.

• PowerShell-7.1.3-win-x64.zip
• PowerShell-7.1.3-win-x86.zip
• PowerShell-7.1.3-win-arm64.zip
• PowerShell-7.1.3-win-arm32.zip

Depending on how you download the file you may need to unblock the file using the Unblock-Filecmdlet. Unzip the contents to the location of your choice and run pwsh.exe from there. Unlikeinstalling the MSI packages, installing the ZIP archive doesn't check for prerequisites. Forremoting over WSMan to work properly, ensure that you've met the prerequisites.

Core Shell Technologies

Use this method to install the ARM-based version of PowerShell on computers like the MicrosoftSurface Pro X. For best results, install PowerShell to the to $env:ProgramFilesPowerShell7folder.

Note

You can use this method to install any version of PowerShell including the latest:

• Stable release: https://aka.ms/powershell-release?tag=stable
• Preview release: https://aka.ms/powershell-release?tag=preview
• LTS release: https://aka.ms/powershell-release?tag=lts

Deploying on Windows 10 IoT Enterprise

Windows 10 IoT Enterprise comes with Windows PowerShell, which we can use to deploy PowerShell 7.

1. Create PSSession to target device

2. Copy the ZIP package to the device

3. Connect to the device and expand the archive

4. Set up remoting to PowerShell 7

5. Connect to PowerShell 7 endpoint on device

Deploying on Windows 10 IoT Core

Windows 10 IoT Core adds Windows PowerShell when you include IOT_POWERSHELL feature, which we canuse to deploy PowerShell 7. The steps defined above for Windows 10 IoT Enterprise can be followedfor IoT Core as well.

For adding the latest PowerShell in the shipping image, use Import-PSCoreRelease command toinclude the package in the workarea and add OPENSRC_POWERSHELL feature to your image.

Note

For ARM64 architecture, Windows PowerShell is not added when you include IOT_POWERSHELL. So thezip based install will not work. You will need to use Import-PSCoreRelease command to add it inthe image.

Deploying on Nano Server

These instructions assume that the Nano Server is a 'headless' OS that has a version of PowerShellis already running on it. For more information, see theNano Server Image Builder documentation.

PowerShell binaries can be deployed using two different methods.

1. Offline - Mount the Nano Server VHD and unzip the contents of the zip file to your chosenlocation within the mounted image.
2. Online - Transfer the zip file over a PowerShell Session and unzip it in your chosen location.

In both cases, you need the Windows 10 x64 ZIP release package. Run the commands within an'Administrator' instance of PowerShell.

Core Shell Nanoparticles

Offline Deployment of PowerShell

1. Use your favorite zip utility to unzip the package to a directory within the mounted Nano Serverimage.
2. Unmount the image and boot it.
3. Connect to the built-in instance of Windows PowerShell.
4. Follow the instructions to create a remoting endpoint using the 'another instance technique'.

Online Deployment of PowerShell

Deploy PowerShell to Nano Server using the following steps.

• Connect to the built-in instance of Windows PowerShell

• Copy the file to the Nano Server instance

• Enter the session

• Extract the ZIP file

• If you want WSMan-based remoting, follow the instructions to create a remoting endpoint using the'another instance technique'.

Install as a .NET Global tool

If you already have the .NET Core SDK installed, it's easy to install PowerShellas a .NET Global tool.

The dotnet tool installer adds $env:USERPROFILE.dotnettools to your $env:PATH environmentvariable. However, the currently running shell doesn't have the updated $env:PATH. You can startPowerShell from a new shell by typing pwsh.

Install PowerShell via Winget

The winget command-line tool enables developers to discover, install, upgrade, remove, andconfigure applications on Windows 10 computers. This tool is the client interface to the WindowsPackage Manager service.

Note

The winget tool is currently a preview. Not all planned functionality is available at this time.You should not use this method in a production deployment scenario. See the winget documentationfor a list of system requirements and install instructions.

The following commands can be used to install PowerShell using the published winget packages:

1. Search for the latest version of PowerShell

2. Install a version of PowerShell using the --exact parameter

Installing from the Microsoft Store

PowerShell 7.1 has been published to the Microsoft Store. You can find the PowerShell release on theMicrosoft Store website or in theStore application in Windows.

Benefits of the Microsoft Store package:

• Automatic updates built right into Windows 10
• Integrates with other software distribution mechanisms like Intune and SCCM

Limitations:

MSIX packages run in an application sandbox that virtualizes access to some filesystem and registrylocations.

• All registry changes under HKEY_CURRENT_USER are copied on write to a private, per-user, per-applocation. Therefore, those values are not available to other applications.
• Any system-level configuration settings stored in $PSHOME cannot be modified. This includes theWSMAN configuration. This prevents remote sessions from connecting to Store-based installs ofPowerShell. User-level configurations and SSH remoting are supported.

For more information, seeUnderstanding how packaged desktop apps run on Windows.

Using the MSIX package

Note

The preview builds of PowerShell include an MSIX package. The MSIX package is not officiallysupported. The package is built for testing purposes during the preview period.

To manually install the MSIX package on a Windows 10 client, download the MSIX package from ourGitHub [releases][releases] page. Scroll down to the Assets section of the Release you want toinstall. The Assets section may be collapsed, so you may need to click to expand it.

The MSIX file looks like this - PowerShell-<version>-win-<os-arch>.msix

To install the package, you must use the Add-AppxPackage cmdlet.

How to create a remoting endpoint

PowerShell supports the PowerShell Remoting Protocol (PSRP) over both WSMan and SSH. For moreinformation, see:

Upgrading an existing installation

For best results when upgrading, you should use the same install method you used when you firstinstalled PowerShell. Each installation method installs PowerShell in a different location. If youare not sure how PowerShell was installed, you can compare the installed location with the packageinformation in this article. If you installed via the MSI package, that information appears in thePrograms and Features Control Panel.

Installation support

Microsoft supports the installation methods in this document. There may be other methods ofinstallation available from other sources. While those tools and methods may work, Microsoft cannotsupport those methods.