Nanoparticle Builder
********************

The Nanoparticle Builder allows you to construct nanoparticles using
the Atomic Simulation Environment (ASE).

See also:

  * ASE: Atomic Simulation Environment

  * ASE nanoparticles and clusters: Nanoparticles


How to use the nanoparticle builder
===================================

1. **Define the crystal** Select an **element** and a **crystal
   structure**.

   Changing either option will try to initialize the lattice constants
   from internal crystal presets: for cubic systems this is **a**, and
   for hexagonal systems this is **a** and **c**. You can then adjust
   these values if necessary.

   Note:

     The lattice constants are initialized only when matching preset
     data is available. If no match is found, enter the values
     manually.

2. **Select the construction method** Choose between **Layer
   specification** and **Wulff construction**.

   Note:

     The **Wulff construction** method is available for **cubic**
     crystal structures only.

3. **Define the directions** Specify the directions used in the
   construction using Miller indices:

   * Cubic systems: 3-number **Miller indices (h k l)**

   * Hexagonal systems: 4-number **Miller–Bravais indices (h k i l)**,
     with **i = -(h + k)**

4. **Specify layers or surface energies** For each direction:

   * **Layer specification**: provide the **number of layers** in that
     direction.

   * **Wulff construction**: provide the **surface energy per area**
     (not per atom).

   The surface-energy unit is irrelevant; only **relative ratios**
   matter.

5. **Direction families and overrides** The first occurrence of a
   direction is interpreted as representing the entire family of that
   direction (for example, specifying "(0 0 1)" also covers symmetry-
   related directions such as "(1 0 0)", "(-1 0 0)", etc., depending
   on the crystal symmetry).

   If a direction (or one of its symmetry-related directions) is
   listed again, the later entry **overrides** the earlier family
   specification for that specific direction. Because of this, the
   **order matters**.

6. **Reorder directions (optional)** Use the **up/down arrows** to
   reorder directions.

7. **Set the Wulff size (Wulff construction only)** Define the
   nanoparticle size using either:

   * **Number of atoms**, or

   * **Diameter (estimated)**

   If you specify a diameter, it is converted into an estimated number
   of atoms assuming a spherical nanoparticle. The rounding option
   (**Above**, **Below**, **Closest**) controls whether the generated
   nanoparticle should have a number of atoms above, below, or closest
   to the requested amount when an exact match is not possible.

8. **Generate the nanoparticle** Click **Generate Nanoparticle** to
   generate it. Then use **Close** to accept and close the builder, or
   **Cancel** to discard it.

After generating a nanoparticle, information about the result is
displayed in the message area below the visualization. If you use
Wulff construction, the inactive size field updates based on the
generated result.


Dry run
=======

Enable **Dry run** to generate and save the Python script without
running it. The script can serve as a starting point for running the
Nanoparticle Builder from Python, or for inspecting the parameters and
process used to create the nanoparticle.
