Dielectric Properties

Tutorial Created with Software Release: 2026-1
Topics: Energy Capture & Storage, Organic Electronics, Pharmaceutical Formulations, Polymeric Materials
Methodology: All-Atom Molecular Dynamics, Molecular Quantum Mechanics
Products Used: Desmond, MS Dielectric, Jaguar, MS Maestro

Tutorial files

1.27 GB
This tutorial is written for use with a 3-button mouse with a scroll wheel.
Words found in the Glossary of Terms are shown like this: Workspacethe 3D display area in the center of the main window, where molecular structures are displayed

 

Tip: You can hover over a glossary term to display its definition. You can click on an image to expand it in the page.
Abstract:

 

In this tutorial, you will learn how to obtain dielectric and optical properties of organic molecules and polymers in Materials Science Maestro.

 

Tutorial Content

  1. Introduction to Dielectric Properties

  1. Creating and Saving the Project

  1. Sketching a Series of Organic Molecules    

  1. Calculating Amorphous Dielectric Properties

  1. Analyzing the Results of the Properties Calculation

  1. Validating the Predictions against Experimental Values

  1. Calculating Dielectric Properties for a Polymer

  1. Conclusion and References

  1. Glossary of Terms                

1. Introduction to Dielectric Properties

The permittivitythe ability of a material to polarize in response to an applied electric field expresses the ability of a material to polarize in response to an applied electric field. The dielectric constanta constant used to relate the permittivity of a material to vacuum, represented by the symbol ɛ (ε) of a material relates its permittivity to vacuum, specifically it is the ratio of the permittivity of the material to that of vacuum. Physically, it means that the greater the polarization developed by a material in an applied field of given strength, the greater the dielectric constant will be.

The refractive indexa measure of how fast light travels through a material, denoted n (n), a measure of how fast light travels through a material, is calculated from the Lorentz-Lorenz equation,

where M is the molecular weight and NA is Avogadro’s number. The static polarizabilitythe tendency of matter to acquire an electric dipole moment in proportion to the applied electric field, denoted ɑ (ɑ), a measure of the tendency of matter to acquire an electric dipole moment in proportion to the applied field when subjected to an electric field, is calculated with quantum mechanical (QM) Jaguar calculations. Frequency dependent polarizability can also be used for the calculation of refractive index versus frequency. The density (⍴) is determined from molecular dynamics (MD) simulations with the OPLS4 force field.

The static permittivity (ϵs), or the permittivity at zero frequency, is calculated from:

The high-frequency permittivity (ϵ∞) is related to the refractive index: ϵ∞ = n2.

The relaxation amplitude ∆ϵ is taken to include only the orientation polarization, evaluated from the MD simulations of the dipole moment, and is given by:

where M is the dipole moment of the unit cell, V is the volume of the unit cell, kB is the Boltzmann constant and T is the temperature (angle brackets <...> represent trajectory average values).

The complex permittivity is calculated from:

where Φ(t) is a time-dependent dielectric decay function, and can be calculated from the autocorrelation of the dipole moment M over the trajectory.

or

The trajectory data for the dielectric decay function is fitted to the Kohlrausch-Williams-Watts (KWW) function:

Where and are adjustable parameters.

For additional background, visit the help documentation on Amorphous Dielectric Properties.

Calculating dielectric properties for organic molecules or polymers is fundamentally useful for many applications. For example, determining dielectric properties may be informative for optics and lens design, chromatography or evaluation of properties of active pharmaceutical ingredients (APIs), to name a few. The procedure demonstrated herein can be implemented for organic molecules as well as polymers.

In this tutorial, we will use the Amorphous Dielectric Properties panel to calculate a variety of dielectric properties for a family of organic small molecules and then a simple polymer. The procedure entails building input models (organic molecules or monomers) and employing a workflow that runs both Jaguar density functional theory (DFT) calculations and Desmond MD simulations to obtain dielectric properties such as refractive index, electric polarizability, static and complex dielectric constants and dielectric loss function. Finally, we will analyze the results and compare the absolute computed quantities to known experimental values to validate the predictions. The Amorphous Dielectric Properties panel supports mixed systems, although this tutorial’s focus will be exclusively on single-molecule systems.

2. Creating and Saving the Project

At the start of the session, change the file path to your chosen Working Directorythe location where files are saved in MS Maestro to make file navigation easier. Each session in MS Maestro begins with a default Scratch Projecta temporary project in which work is not saved, closing a scratch project removes all current work and begins a new scratch project, which is not saved. A MS Maestro project stores all your data and has a .prj extension. A project may contain numerous entries corresponding to imported structures, as well as the output of modeling-related tasks. Once a project is saved, the project is automatically saved each time a change is made.

Structures can be built in MS Maestro or can be imported using File > Import Structures (or drag-and-dropped), and are added to the Entry Lista simplified view of the Project Table that allows you to perform basic operations such as selection and inclusion and Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data. The Entry Lista simplified view of the Project Table that allows you to perform basic operations such as selection and inclusion is located to the left of the Workspacethe 3D display area in the center of the main window, where molecular structures are displayed. The Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data can be accessed by Ctrl+T (Cmd+T) or Window > Project Table if you would like to see an expanded view of your project data.

  1. Double-click the Materials Science icon

Figure 2-1. Change Working Directory option.

  1. Go to File > Change Working Directory
  2. Find your directory, and click Choose
  3. Pre-generated input and results files are included for running jobs or examining output. Download the zip file here: schrodinger.com/sites/default/files/s3/release/current/Tutorials/zip/dielectric.zip
  4. After downloading the zip file, unzip the contents in your Working Directorythe location where files are saved for ease of access throughout the tutorial

Figure 2-2. Save Project panel.

  1. Go to File > Save Project As
  2. Change the File name to dielectric_tutorial, click Save
    • The project is now named dielectric_tutorial.prj

3. Sketching a Series of Organic Molecules

In this section, we will prepare a small library of organic molecules for analysis.

organic molecules to be studied

Figure 3-1. Sketching and saving ethylene carbonate.

To skip drawing and proceed directly to setting up the dielectric job, go to File > Import Structures, navigate to the tutorial files and import organic_molecules.mae. Then proceed to Section 4. Otherwise:

  1. From the main menu, go to Edit > 2D Sketcher
    • The 2D Sketcher opens
  2. Sketch an ethylene carbonate (EC) molecule
  3. Click Save as New and name the entry: EC, then click OK
    • An ethylene carbonate molecule is includedthe entry is represented in the Workspace, the circle in the In column is blue in the workspacethe 3D display area in the center of the main window, where molecular structures are displayed and is selected(1) the atoms are chosen in the Workspace. These atoms are referred to as "the selection" or "the atom selection". Workspace operations are performed on the selected atoms. (2) The entry is chosen in the Entry List (and Project Table) and the row for the entry is highlighted. Project operations are performed on all selected entries in the entry list

 

Note: For a complete overview of using the sketcher panel, see the 2D Sketcher Panel documentation

Figure 3-2. The ten entries in the entry list.

  1. Proceed to sketch the 9 additional molecules (shown above), following the same procedure and saving each as a new entry with a corresponding name

Figure 3-3. Include all molecules and tile the entries.

Optional: All of the molecules can be shown in the workspace simultaneously by including all of the entries and using the Show Workspace Configurational Panel button () > Tile by button in the bottom right corner of the workspacethe 3D display area in the center of the main window, where molecular structures are displayed

Figure 3-4. Applying ball-and-stick representation.

Optional: If not already, change to a ball-and-stick representation by clicking Style > Apply ball-and-stick representation or choose any style that you prefer.

4. Calculating Amorphous Dielectric Properties

In this section, we will calculate various dielectric properties of the prepared molecules using an automated workflow driven by the Amorphous Dielectric Properties panel.

Figure 4-1. Selecting the ten entries and opening the panel.

  1. Select(1) the atoms are chosen in the Workspace. These atoms are referred to as "the selection" or "the atom selection". Workspace operations are performed on the selected atoms. (2) The entry is chosen in the Entry List (and Project Table) and the row for the entry is highlighted. Project operations are performed on all selected entries all ten organic molecules from the entry lista simplified view of the Project Table that allows you to perform basic operations such as selection and inclusion
  2. Go to Tasks > Materials > Classical Mechanics > Amorphous Dielectric Properties > Amorphous Dielectric Properties Calculations

Figure 4-2. Setting the parameters for the Amorphous Dielectric Properties calculation.

  1. For Use structures from, maintain Project Table (10 selected entries)
  2. Maintain all of the Property selections: Refractive index, Abbe number, Static dielectric constant and Complex permittivity
  3. In the Polarizability section, maintain the Jaguar settings and check Over a range of wavelength between
    • This will initiate a frequency dependent polarizability calculation
  4. Change in steps of to 100 nm
    • For example purposes, we will only look at the 4 wavelengths designated by this range plus, by default when we select Abbe number, 486.1, 589.3 and 656.3 nm frequency dependent polarizability will be calculated 
  5. For Number of molecules, input 1000
  6. Input 1 ns for Permittivity production time
    • In practice, longer simulation times provide better accuracy for dipole autocorrelation functions. Here, we will use a shorter time for ease of demonstration. However, the results for small organic molecules like these will still be high-quality
  7. Input 1 ps for Dipole recording interval

Note: Checking Use input structures as monomers will update the panel parameters for polymeric systems. This functionality will be demonstrated in Section 7

Figure 4-3. Run settings for the Amorphous Dielectric Properties calculation.

  1. Change the Job name to dielectric_prop_ten-molecules-t1
  2. Adjust the job settings () as needed
    • This job takes ~3 hours on a 12 CPU host / 1 GPU host
    • This workflow requires both CPU and GPU hosts for handling both DFT and MD
  3. If you would like to run the job, click Run. Otherwise, pre-generated files are available for proceeding in Section 5

Here are some additional notes regarding the Amorphous Dielectric Properties panel for consideration:

  • Frequency dependent refractive index can be obtained, as set above, by selecting the range of wavelengths of interest.  To calculate Abbe number, the Abbe number property must also be selected.
  • Refractive Index, Abbe number, Static dielectric and Complex permittivity for unconjugated homopolymers may also be calculated by enabling the Create polymers from monomers option and inputting of monomer structure. Defaults for the settings will update with enabling of polymers. Polymers and molecules can not be mixed in the Use structures from Project Table option. See Section 7 for a polymer example.
  • The Jaguar settings for the optimization and polarizability calculations can be changed, though the default functional and basis sets have been selected based on high quality benchmarking. For larger molecules and calculation of frequency dependent refractive index, DEF2-SVPD basis set is recommended as it provides faster calculation with limited reduction in accuracy.  An increased accuracy level may be needed for larger polymer monomers. Additionally, the average electric polarizability per molecule can be set.
  • This example uses a relatively small number of molecules in the unit cell (1000). In practice, about 20,000 atoms in the unit cell is a good benchmark, but there is a tradeoff between computational expense and accuracy.  If the density is reproduced well (within 1-2%), the parameters are most likely reasonable.
  • Consider additional replicates, particularly if there are high rotational barriers in the system, to ensure a good sampling of initial structures.
  • The default ensemble class (NVE) is for calculating the dielectric properties. In the workflow, the system is equilibrated first by standard protocols starting with a low density system using an NPT ensemble class.
  • The example simulation time, time step and trajectory recording intervals are reasonable defaults, and can be changed depending on the system. One should always consider memory capacity when choosing recording intervals.
  • The equilibration temperature is the fixed temperature for the NPT ensemble during equilibration.

Further information is available in the help documentation: Amorphous Dielectric Properties.

5. Analyzing the Results of the Properties Calculation

In this section, we will analyze the results of the Amorphous Dielectric Properties calculation. You will be able to proceed with pre-generated results or you can use the complete output of Section 4 above.

Figure 5-1. Importing a pre-generated output file.

If you have run the calculations yourself, proceed to Step 5 with the incorporated output from Section 4. Otherwise:

  1. From the main menu, choose File > Import Structures
  2. Navigate to where you downloaded the tutorial files. Open the dielectric_prop_ten-molecules-t1-002 directory (associated with water) and choose the Section_04 > dielectric_prop_ten-molecules-t1-002 > dielectric_prop_ten-molecules-t1-002-out.cms file
  3. Click Open
    • A new entry group is added to the entry lista simplified view of the Project Table that allows you to perform basic operations such as selection and inclusion. The entry is automatically selected(1) the atoms are chosen in the Workspace. These atoms are referred to as "the selection" or "the atom selection". Workspace operations are performed on the selected atoms. (2) The entry is chosen in the Entry List (and Project Table) and the row for the entry is highlighted. Project operations are performed on all selected entries and includedthe entry is represented in the Workspace, the circle in the In column is blue
  4. Repeat the import procedure for ethylene carbonate: dielectric_prop_ten-molecules-t1-001-out.cms

 

Only the outputs for water are discussed here. This is sufficient to proceed with the analysis. For a complete validation of the results from other runs, you can proceed to Section 6.

Note: The workflow includes many jobs per molecule. The associated data from each segment of the workflow is available in the output files. For example, the trajectory from the MD stages can be imported and analyzed

Figure 5-2. Accessing the results through the Working Action Menu (WAM) button.

Each of the results has a workflow action menu (WAM) button associated with it:

  1. Click the WAM button associated with the water unit cell and select Amorphous Dielectric Properties Results…

Figure 5-3. Property outputs from the workflow.

The panel includes a Summary tab and three viewers: Refractive Index, Complex Permittivity and Decay Function

The top half of the Summary tab shows the system information: number of atoms, number of molecules, etc. It also shows the properties that are available for analysis.

In the bottom half of the panel, the polarizability, refractive index, Abbe number, static dielectric constant and high-frequency dielectric constant as a result of the complex permittivity workflow are shown.

Figure 5-4. Refractive Index

  1. Go to the Refractive Index tab

A plot is shown of the refractive index versus wavelength, including the data points associated with the specified wavelength range and the three wavelengths utilized to compute Abbe number (486.1, 589.31 and 656.31 nm)

Figure 5-5. Complex Permittivity function within the amorphous dielectric viewer.

  1. Go to the Complex Permittivity tab

 

The Epsilon(Real) vs Frequency and Epsilon(Imaginary) vs frequency spectrums are shown

The Type dropdown menu has options to display Complex Plane and Loss Tangent plots. The Dielectric loss peak position is printed.

For more information about the plots and terms shown in this tab, please visit the help documentation.

Figure 5-6. Dielectric decay function.

  1. Proceed to the Decay Function tab

 

The plot of the Dielectric Decay function vs. time (Tau in this case) is shown

The toolbar has tools for manipulating the plot and saving data or images

The lower and upper limits of Tau can be changed (either by clicking and dragging on the blue dashed lines or inputting the quantities) for fitting the KWW function to obtain the complex permittivity function

  1. Close the Amorphous Dielectric Viewer

6. Validating the Predictions Against Experimental Values

In this section, we will export data on all of the observables of interest and compare some quantities to experimental results.

Figure 6-1. Importing structures.

  1. Proceed to import the outputs from the previous calculations for the rest of the molecules. Go to File > Import Structures
  2. Navigate to where you downloaded the tutorial files. Open the Section_04 > dielectric_prop_ten-molecules-t1-00n > dielectric_prop_ten-molecules-t1-00n-out.cms files

 

Figure 6-2. Opening the Project Table and selecting the relevant entries.

 

  1. Open the Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data ()
    • The Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data will appear on the main screen, containing many different properties
  2. Select(1) the atoms are chosen in the Workspace. These atoms are referred to as "the selection" or "the atom selection". Workspace operations are performed on the selected atoms. (2) The entry is chosen in the Entry List (and Project Table) and the row for the entry is highlighted. Project operations are performed on all selected entries the ten result entries

 

Note: Depending on your preferences and/or previous interactions with the Project Table, your property columns may not match the tutorial figures exactly.

 

Figure 6-3. Hiding properties.

The Property Tree will display default properties

  1. To generate a table with just the results of interest, begin by clicking the button, and Hide All
    • The Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data updates to only display Row, Included and Title

Figure 6-4. Selecting properties of interest from the Property Tree.

  1. Navigate the Property Tree to check the following properties of interest:
    • Maestro: Entry ID
    • Materials Science > Primary: Relative Static Permittivity, Electric Polarizability (bohr^3), Refractive Index, Density (g/cm3)
    • Materials Science > Secondary: Abbe Number, Maximum Dielectric Loss, Frequency of Maximum Dielectric Loss (Hz), Temperature (K)
    • The nine selected properties appear in the Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data

Note: The columns appear in the Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data in the order that they are selected from the Property Tree. The order can also be changed by clicking and dragging the column headers

Figure 6-5. Exporting to a spreadsheet.

  1. Right-click on any of the data-containing rows, and click Export > Spreadsheet…
  2. Navigate to the directory where you want to save the .csv file with the parameters of interest

Figure 6-6. Exporting options.

  1. In the Options << section, make the following selections:
    • Entries: Selected
    • Properties: Shown
    • Delimiter: comma
    • Precision: Full
  2. For File name, input dielectric_prop1 and click Save
  3. Close the Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data

The dielectric_prop1.csv file can be opened with any standard spreadsheet tool. To make a comparison with experiment, experimental values can be found in a variety of public sources or publications. Below is a graphical compilation of our findings confirming the accuracy of the methodology for some of the key properties. Feel free to perform the analysis on your own for practice, or to confirm any of the other properties.

 

 

7. Calculating Dielectric Properties for a Polymer

In this section, we will demonstrate how to use the Amorphous Dielectric Properties Calculation and Viewer panels to predict the refractive index and dielectric constant for a simple polymer, polyethylene glycol (PEG).

Figure 7-1. Sketching the monomer.

  1. From the main menu, go to Edit > 2D Sketcher
    • The 2D Sketcher opens
  2. Sketch ethanol (see the Figure)
  3. Click Save as New and name the entry: monomer, then click OK
  4. Close the 2D Sketcher

Optional: Feel free to stylize the molecule in the workspace however you prefer

Figure 7-2. Selecting and including the entry and opening the panel.

  1. With the monomer entry selected(1) the atoms are chosen in the Workspace. These atoms are referred to as "the selection" or "the atom selection". Workspace operations are performed on the selected atoms. (2) The entry is chosen in the Entry List (and Project Table) and the row for the entry is highlighted. Project operations are performed on all selected entries and includedthe entry is represented in the Workspace, the circle in the In column is blue, go to Tasks > Materials > Classical Mechanics > Amorphous Dielectric Properties > Amorphous Dielectric Properties Calculations

Figure 7-3. Resetting the panel.

  1. Reset the panel using the button at the bottom left corner of the panel.

Figure 7-4. Switching to polymer input.

  1. Check Use input structures as monomers
    • The panel updates to the polymer defaults
  2. Click Mark head and tail
    • A new overlaid panel appears

Figure 7-5. Selecting the head and the tail.

  1. Keep the panel open, and in the workspace, pick the oxygen as the head atom
    • The oxygen and its bound hydrogen are selected in the workspace
  2. Pick the opposite carbon as the tail atom
    • The carbon and one of its bound hydrogens are selected in the workspace
  3. Back in the panel, click Save Monomer
    • The panel updates with a molecular formula (C2H4O) and a name (which can be edited), in this case, monomer

Note: To confirm you have properly defined your repeat unit, hover over the molecular formula to see a 2D Sketch of the monomer with the head and tail defined by R groups.

Figure 7-6. Setting the parameters for the Amorphous Dielectric Properties calculation.

  1. For Number of monomers retain 25
    • This quantity is the number of monomers per polymer’s chain
  2. For Maximum oligomer size input 5
    • The workflow requires DFT calculations. For a polymer, calculations are performed for a series of oligomers to ensure convergence
    • Be mindful that if your repeat unit is very large, calling for many monomers will result in computationally expensive DFT calculations
  3. For Number of polymers input 100
    • This input will result in 100 25-mers which will generate a reasonably sized box for MD
  4. For Number of replicates input 3
    • Sampling will improve the quality of the results
  5. Change the Dipole recording interval to 500 ps

Note: The number of trajectory records (frames) does not have to be too large. The dipole recording interval should be set to 50 ps or less if high frequency decay is expected

Figure 7-7. Naming and running the job.

  1. Change the Job name to dielectric_prop_PEG
  2. Adjust the job settings () as needed
    • This job takes ~6 hours on a 12 CPU / 3 GPU host
    • This workflow requires both CPU and GPU hosts for handling both DFT and MD
  3. If you would like to run the job, click Run. Otherwise, import dielectric_prop_PEG-out.cms from the provided tutorial files

Figure 7-8. The output in the entry list and workspace.

When the job completes or after importing, a new entry is added to the entry lista simplified view of the Project Table that allows you to perform basic operations such as selection and inclusion titled disorder_system_builder_r1_all_components_amorphous. One of the replicates can be visualized in the workspace.

Figure 7-9. The data printed in the Project Table.

The key properties (density, static dielectric constant and refractive index) can be found either in the Amorphous Dielectric Viewer panel or in the Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data. First, we will view the results in the Project Table

  1. Open the Project Tabledisplays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data () and view the calculated properties

The computed density of 1.109 g/cm3, refractive index of 1.482 and dielectric constant of 10.543 agree quite well with known quantities for PEG. For example, PEG 400 at room temperature has a reported density of 1.126 g/cm3, refractive index of 1.467 and dielectric constant of 12.5.

Figure 7-10. Accessing the results through the Working Action Menu (WAM) button.

Now, we will briefly analyze the results using the Amorphous Dielectric Viewer panel.

  1. Click the WAM button associated with the water unit cell and select Amorphous Dielectric Properties Results…

Figure 7-11. Property outputs from the workflow.

In the Summary tab of the panel, the polarizability, refractive index, Abbe number, static dielectric constant and high-frequency dielectric constant as a result of the complex permittivity workflow are shown.

Figure 7-12. Refractive Index viewer.

  1. Go to the Refractive Index tab

A plot is shown of the refractive index versus wavelength, including the data points associated with the three wavelengths utilized to compute Abbe number (486.1, 589.31 and 656.31 nm).

 

Figure 7-13. Dielectric decay function viewer.

  1. Proceed to the Decay Function tab

 

The plot of the Dielectric Decay function vs. time (Tau in this case) is shown

The toolbar has tools for manipulating the plot and saving data or images

The lower and upper limits of Tau can be changed (either by clicking and dragging on the blue dashed lines or inputting the quantities) for fitting the KWW function to obtain the complex permittivity function

Feel free to continue exploring the Amorphous Dielectric Viewer as interested

  1. Close the Amorphous Dielectric Viewer

8. Conclusions and References

In this tutorial, we performed a workflow to calculate dielectric properties. Different observables related to dielectric and optical properties were obtained. Comparison of the obtained properties such as density, refractive index and relative static permittivity show good agreement with experiment. The procedure applied in this tutorial can be used for other organic molecules as well as polymers.

For further learning:

For introductory content, focused on navigating the Schrödinger Materials Science interface, an Introduction to Materials Science Maestro tutorial is available. Please visit the materials science training website for access to 100+ tutorials. For scientific inquiries or technical troubleshooting, submit a ticket to our Technical Support Scientists at help@schrodinger.com. 

For self-paced, asynchronous, online courses in Materials Science modeling, including access to Schrödinger software, please visit the Schrödinger Online Learning portal on our website.

For some related practice, proceed to explore other relevant tutorials:

For further reading:

9. Glossary of Terms

Dielectric constant - a constant used to relate the permittivity of a material to vacuum, represented by the symbol ɛ

Entry List - a simplified view of the Project Table that allows you to perform basic operations such as selection and inclusion

Included - the entry is represented in the Workspace, the circle in the In column is blue

Permittivity - the ability of a material to polarize in response to an applied electric field

Project Table - displays the contents of a project and is also an interface for performing operations on selected entries, viewing properties, and organizing structures and data

Refractive index - a measure of how fast light travels through a material, denoted n

Scratch Project - a temporary project in which work is not saved, closing a scratch project removes all current work and begins a new scratch project

Selected - (1) the atoms are chosen in the Workspace. These atoms are referred to as "the selection" or "the atom selection". Workspace operations are performed on the selected atoms. (2) The entry is chosen in the Entry List (and Project Table) and the row for the entry is highlighted. Project operations are performed on all selected entries

Static permittivity - the permittivity at zero frequency, denoted ϵs

Static polarizability - the tendency of matter to acquire an electric dipole moment in proportion to the applied electric field, denoted ɑ

Working Directory - the location where files are saved

Workspace - the 3D display area in the center of the main window, where molecular structures are displayed