.. _single_point :

Single Point Energy
===================

Overview
--------

Single Point Energy (SPE) calculations compute the electronic energy of a molecule 
at a fixed geometry without optimizing the atomic positions. This is fundamental 
for understanding molecular stability, comparing conformers, and serving as a 
starting point for other calculations.

Check the :ref:`visualiser-input` section for the allowed input types and how to upload the files.

Modules Available
-----------------

Three modules are currently available for SPE calculations:

1. **DFT** - Density Functional Theory (highest accuracy)
2. **GFN2-XTB** - Tight-binding semi-empirical method (fast and reasonably accurate)
3. **Hybrid ML model** - Fastest and DFT-accurate using machine learning

Hybrid ML Module Input Fields
-----------------------------
Upon selecting the **Hybrid ML** module, following inputs have to be provided: 

.. grid:: 1 2 2 2
   :gutter: 2

   .. grid-item-card:: **Charge**
      :text-align: left 

      Total charge of the molecule (e.g., 0)

   .. grid-item-card:: **Multiplicity**
      :text-align: left 

      Spin mulitplicity = 2S+1 (e.g., 1 for singlet)

GFN2-XTB Module Input Fields
----------------------------

If the **GFN2-XTB** module is selected, the following inputs must be provided: 

.. grid:: 1 2 2 2 
   :gutter: 2 

   .. grid-item-card:: **Charge**
      :text-align: left

      Total charge of the molecule (e.g., 0)

   .. grid-item-card:: **Multiplicity**
      :text-align: left 

      Spin multiplicity = 2S+1 (e.g., 1 for singlet)

   .. grid-item-card:: **Include Solvent** 
      :text-align: left 

      Toggle to include solvent effects

   .. grid-item-card:: **Solvent**
      :text-align: left
      
      Select a solvent (e.g., water, ethanol)

DFT Module Input Fields
-----------------------

Upon selecting the **DFT** module, the following inputs must be provided:

.. grid:: 1 2 2 2
   :gutter: 2

   .. grid-item-card:: **Charge**
      :text-align: left

      Total charge of the molecule (e.g., 0)

   .. grid-item-card:: **Multiplicity**
      :text-align: left

      Spin multiplicity = 2S+1 (e.g., 1 for singlet)

   .. grid-item-card:: **Basis Set Category**
      :text-align: left

      Select the basis set family (e.g., Pople, Dunning)

   .. grid-item-card:: **Basis Set**
      :text-align: left

      Select the basis set (e.g., 6-31G, 6-31+Gss)

   .. grid-item-card:: **Exchange Functional**
      :text-align: left

      Choose an exchange-correlation functional (e.g., B3LYP)

   .. grid-item-card:: **Add Dispersion Correction**
      :text-align: left

      Toggle to enable dispersion correction (e.g., D3BJ)

   .. grid-item-card:: **Add Solvent**
      :text-align: left

      Toggle to include solvent effects

   .. grid-item-card:: **Solvent**
      :text-align: left

      Select a solvent (e.g., water, ethanol)

   .. grid-item-card:: **Solvent Model**
      :text-align: left

      Choose the solvation model (e.g., PCM, SMD)

   .. grid-item-card:: **Dispersion Correction**
      :text-align: left

      Choose a dispersion correction model

   .. grid-item-card:: **Number of Orbitals**
      :text-align: left

      Specify the number of orbitals (e.g., 5) [This is under development]

.. note::
    We have LDA, PBE, PBE0, M06, B3LYP, CAM-B3LYP and WB97X functionals
    available right now for the GPU calculations.

Finally, click the **Run Calculation** button to start the simulation.

Output Details
--------------

The following options are available to explore and save the results of your geometry optimization:

.. grid:: 1 1 1 1
   :gutter: 2

   .. grid-item-card:: **Metadata**
      :text-align: left

      In the metadata section, you can view all the task details including the 
      total energy.