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Partial charges: read every scheme ORCA, Gaussian and NWChem provide, and show them like Mulliken

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
30/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Active
Tech stack
c
Domain
data

Research direction

Start by tracing how Mulliken and ESP charges are parsed into the per-atom tables and displayed through data/client/config/PropertyPanelDescriptor.xml. Then add support in the listed order, checking each parser against real ORCA, Gaussian, and NWChem outputs and verifying that the atomic charges sum to the total charge. The issue also proposes a unified scheme selector, comparison table, and comparable colour scales.

Written by the indexing model from the issue text.

Description

Requested for research use (partial charges). Today ECCE reads Mulliken (NWChem, ORCA, Gaussian, MOPAC, ECCE-QM), ESP fits (NWChem esp, Gaussian MK/CHELPG) and ORCA CHELPG when requested. Everything else the codes provide is ignored.

Not read yet

Scheme ORCA Gaussian 16 NWChem
Löwdin printed by default — printed on request
Mayer (atomic charge, bond orders) printed by default "Do Mayer BO" offered, output not read —
Hirshfeld ! Hirshfeld Pop=Hirshfeld —
CM5 — with Pop=Hirshfeld —
MBIS ! MBIS (ORCA 5+) — —
NPA (NBO) with NBO Pop=NBO6 already offered, NPA not read via NBO's file
APT — printed with Freq —

Order (cheapest first):

  1. Read what is printed already: ORCA Löwdin and Mayer, Gaussian NPA (already requestable) and APT.
  2. Offer and read Hirshfeld (ORCA, Gaussian), CM5 (Gaussian), MBIS (ORCA) in the Calculation Editor.
  3. NWChem Löwdin; NBO for ORCA and NWChem if the NBO program is available.

Display: the general PartialCharges panel (table, colour scale, atoms coloured by charge; used for ESPCHARGE) can show each new property by declaring it in data/client/config/PropertyPanelDescriptor.xml (group Charges, class PartialCharges), as long as the parse scripts store the same per-atom table. On top of that:

  • one "Atomic charges" entry with a scheme choice, instead of one menu entry per scheme;
  • a comparison table (atoms × schemes), optionally a plot of charge per atom for each scheme;
  • the same, optionally fixed, colour scale across schemes so colours are comparable.

Verification: each scheme checked against a real output of that code (water, a small ion pair, a transition-metal complex), with sums matching the total charge, as in the teaching set.

Dominant language
C
Stars
10
Forks
8
Avg merge
21m
Merged PRs (30d)
1

Getting set up

This project ships no dev container, Dockerfile or contributing guide, so setting up is up to you: start from its README, and see our first-contribution guide for the general steps.

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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