sci_form/scf/constants.rs
1//! Physical and mathematical constants for quantum chemistry.
2//!
3//! All values follow CODATA 2018 recommended values.
4
5/// Conversion: 1 Å = 1.8897259886 Bohr.
6pub const ANGSTROM_TO_BOHR: f64 = 1.8897259886;
7
8/// Conversion: 1 Bohr = 0.529177 Å.
9pub const BOHR_TO_ANGSTROM: f64 = 0.52917721067;
10
11/// 1 Hartree = 27.211386 eV.
12pub const HARTREE_TO_EV: f64 = 27.211386245988;
13
14/// 1 eV = 0.0367493 Hartree.
15pub const EV_TO_HARTREE: f64 = 1.0 / HARTREE_TO_EV;
16
17/// 1 Hartree = 627.5095 kcal/mol.
18pub const HARTREE_TO_KCAL: f64 = 627.5094740631;
19
20/// Default SCF max iterations.
21pub const SCF_MAX_ITER: usize = 128;
22
23/// Default SCF energy convergence threshold (Hartree).
24pub const SCF_ENERGY_THRESHOLD: f64 = 1e-8;
25
26/// Default SCF density convergence threshold.
27pub const SCF_DENSITY_THRESHOLD: f64 = 1e-6;
28
29/// Default DIIS subspace size.
30pub const DIIS_SUBSPACE_SIZE: usize = 8;