Examples for PSCF (polymer self-consistent field theory)

This directory contains a collection of input files for examples that can be run with the PSCF polymer self-consistent field theory software. PSCF is a fortran program that can be used to compute properties of periodic microstructures of block copolymer materials. These examples are provided to demonstrate the contents and syntax of the file formats used by PSCF, and as potentially useful starting points for new simulations.

The home page for the PSCF package is located at: http://morse.cems.umn.edu/morse/code/pscf/home.php.html The PSCF home page provides links to the user documentation and source code, and downloadable binary installers for some operating systems. The fortran source code for PSCF is maintained in the github repository: https://github.com/dmorse/pscf

Directory Structure

The top level subdirectories of this repository each contain examples of simulations involving different types of system. The main subdirectories are currently:

diblock/

triblock/

solution/

Directory diblock/ contains examples for neat (one-component) diblock copolymer melts. Directory triblock/ contains examples for neat ABC triblock terpolymer melts. Directory ssolution/ contains examples of ordered phases of a mixture of diblock copolymer and a selective small molecule solvent. We will refer to these top level subdirectories in what follows as "system level" directories.

Each ubdirectory of these system level directoires contains simulations of a different possible phase (i.e., crystal structure) of the system of interest. The names of these subdirectories are abbreviations of the names of the phases: lam for lamellar, hex for hexagonally packed cylinders, gyr for gyroid, etc. Each system level subdirectory contains a CONTENTS file explaining these abbrevations in greater detail.

Directories that contain simulations of a particular phase may either contain either the input files for a single example, or subdirectories containing several examples of the same phase. Some such directories contain two subdirectories named iterate/ and sweep/. In this case, the iterate/ directory contains an example of a simulation that solves the SCF equations for a single set of parameters, and the sweep/ directory contains an example that uses the SWEEP parameter file command to perform a series of simulations along a line through parameter space.

Example Directory Contents

In what follows, we refer to a directory that contains the input files for a single example or several closely related examples that share some input files as an example directory. In each example directory, there are two types of input files, named

• in.omega: an input omega (chemical potential) field
• param* : a parameter file or files

Each example directory contains only one input omega file, but may contain one or more param files with instructions for slightly different simulations. In example directories that contain more than one parameter files, the parameter file for the simplest example is usually named simply 'param'.

Almost all example directories contains an initially empty subdirectory named 'out/'. Output files will be created in this directory when you run an example.

Running an an example:

To run an example:

• Change directory (cd) into the example directory of interest.

• Enter the command: pscf < paramfile

Here "paramfile" denotes the name of a particular parameter file.
This above command will run the example while outputting information reporting the progress of the calculation to the screen. Alternatively, the command

pscf < paramfile > out/log &

will run the example in the background and output this information to a file named "log" in the out/ sub-directory.

Output files

ITERATE Examples:

Examples that solve the SCFT equations for a single set of input parameters create the following output files in the out/ directory:

  out/out   = output summary 
  out/rho   = output monomer volume fraction fields
  out/omega = output omega fields

SWEEP Examples:

Examples in which the parameter file contains a SWEEP command cause the program to solve the SCF equations for a set of input parameters along a line in parameter space. The SWEEP command can specify any line along which one or more of the parameters are incremented in uniform increments, with increment values that are specified in the input script. The output files produced by running a SWEEP example are also placed in the out subdirectory, and have names of the form

 out/$(N)out     = output summary fields
 out/$(N)rho     = output density fields
 out/$(N)omega   = output omega fields

where $(N) takes on integer values 0, 1, 2, etc. That is, the directory will contain output summary files out/0.out, out/1.out, etc. and a similar sequence of number rho (volume fraction) files named out/0.rho, out/1.rho, etc, and numbered output chemical potential files named out/0.omega, out/1.omega, etc.