ARCHIVE!

This repo is going to be archived, as this was my first successful HF code, which I have now improved and started from scratch, see the new repo here

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SCF_MRJD_RS

Background info about the project

This project started out of curiosity to understand the fundamentals of Hartree-Fock (HF) calculations. As I only had an "overview" lecture in my Bachelor's degree which did not include the necessary details for a broader understanding of the subject, I decided to combine my interest in Rust and computational chemistry and implement a "simple" HF programme.

As a starting point I used the tutorials from the Crawford's group, which can be found at the following link: C++ Programming Tutorial in Chemistry

Although the tutorials are written in C++, I decided to implement the code in Rust. I did also start a C++ version of the code, but I decided to focus on the Rust version.

My Rust implementation is not a direct translation of the C++ code, but I tried to keep the same structure and the same naming conventions.

The code for the Crawford's group tutorials can be found in src/Crawford_projects. I am going to use part of the code from the tutorials to implement the Hartree-Fock SCF algorithm.

Parts that are implemented

• Molecular integrals ($T_\text{el}, V_\text{eN}, V_\text{NN}, V_\text{ee}$) which are needed for RHF SCF using McMurchie-Davidson algorithm

• Dipole integrals (Mu-Tensor ($3\times N \times N$))

• Bad $N^8$ scaling MP2 (better: $N^5$ soon)

• Basic geometry analysis (Angles, OOP, Dihedrals, Inertia tensor, Analysis of geometry, Rotor classification)

PLANNED:

• Better geometry analysis (using vdW radii for better classification of which bond distances are necessary + which angles are necessary)

• Transform integrals from cartesian (Hermite) basis functions to pure regular solid harmonics

Dependencies

• Rust

• OpenBLAS (including the LAPACK implementation)

  

  # Arch based Linux distro:
  yay -S openblas-lapack
  
  # Ubuntu based Linux distro:
  sudo apt install libopenblas-dev

• libgsl-dev

  

  # Arch based Linux distro:
  yay -S gsl
  
  # Ubuntu based Linux distro:
  sudo apt install libgsl-dev

Sources / Thank you

This project would not have been possible without the great introductory PDF by Joshua Goings (@jjgoings) and his Python / Cython implementation of McMurchie-Davidson.

When starting this project the integral routines were quite a lot to learn, so in the beginning I translated his Python code to idiomatic Rust (to my understanding) and then tried to simplify things to my understanding.

Although the integral routines are mostly a copy, the structure of the code and the "building blocks" are made by myself.

Another thanks I would like to give to PySCF, which gave me the initial idea for a parser of .gbs files of basis set data, provided by BasisSetExchange