sci_form/dos/
multi_method.rs

1//! Multi-method DOS: use orbital energies from EHT, PM3, xTB, or HF-3c.
2//!
3//! Provides a unified API for computing DOS from any supported electronic
4//! structure method, choosing the appropriate level of theory via `DosMethod`.
5
6use super::dos::compute_dos;
7use serde::{Deserialize, Serialize};
8
9/// Method for obtaining orbital energies for DOS computation.
10#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
11pub enum DosMethod {
12    /// Extended Hückel Theory (fastest, qualitative).
13    Eht,
14    /// PM3 semi-empirical (good for organic molecules).
15    Pm3,
16    /// GFN-xTB tight-binding (good for organometallics).
17    Xtb,
18    /// GFN1-xTB (improved dispersion).
19    Gfn1,
20    /// GFN2-xTB (multipole electrostatics).
21    Gfn2,
22    /// HF-3c minimal Hartree-Fock.
23    Hf3c,
24}
25
26/// Multi-method DOS result extending base DosResult.
27#[derive(Debug, Clone, Serialize, Deserialize)]
28pub struct MultiMethodDosResult {
29    /// Energy grid (eV).
30    pub energies: Vec<f64>,
31    /// Total DOS (states/eV).
32    pub total_dos: Vec<f64>,
33    /// Method used.
34    pub method: DosMethod,
35    /// HOMO energy (eV).
36    pub homo_energy: f64,
37    /// LUMO energy (eV).
38    pub lumo_energy: f64,
39    /// HOMO-LUMO gap (eV).
40    pub gap: f64,
41    /// Orbital energies used (eV).
42    pub orbital_energies: Vec<f64>,
43    /// Smearing width (eV).
44    pub sigma: f64,
45}
46
47/// Compute DOS using a specified electronic structure method.
48///
49/// Runs the chosen method to obtain orbital energies, then broadens
50/// them with Gaussian smearing to produce the DOS.
51pub fn compute_dos_multimethod(
52    elements: &[u8],
53    positions: &[[f64; 3]],
54    method: DosMethod,
55    sigma: f64,
56    e_min: f64,
57    e_max: f64,
58    n_points: usize,
59) -> Result<MultiMethodDosResult, String> {
60    // Get orbital energies from the specified method
61    let (orbital_energies, homo_energy, lumo_energy, gap) = match method {
62        DosMethod::Eht => {
63            let eht_result = crate::eht::solve_eht(elements, positions, None)?;
64            let homo = eht_result.homo_energy;
65            let lumo = eht_result.lumo_energy;
66            (eht_result.energies, homo, lumo, eht_result.gap)
67        }
68        DosMethod::Pm3 => {
69            let pm3 = crate::compute_pm3(elements, positions)?;
70            let homo = pm3.homo_energy;
71            let lumo = pm3.lumo_energy;
72            (pm3.orbital_energies, homo, lumo, pm3.gap)
73        }
74        DosMethod::Xtb => {
75            let xtb = crate::xtb::solve_xtb(elements, positions)?;
76            let homo = xtb.homo_energy;
77            let lumo = xtb.lumo_energy;
78            (xtb.orbital_energies, homo, lumo, xtb.gap)
79        }
80        DosMethod::Gfn1 => {
81            let gfn1 = crate::xtb::gfn1::solve_gfn1(elements, positions)?;
82            let homo = gfn1.homo_energy;
83            let lumo = gfn1.lumo_energy;
84            (gfn1.orbital_energies, homo, lumo, gfn1.gap)
85        }
86        DosMethod::Gfn2 => {
87            let gfn2 = crate::xtb::gfn2::solve_gfn2(elements, positions)?;
88            let homo = gfn2.homo_energy;
89            let lumo = gfn2.lumo_energy;
90            (gfn2.orbital_energies, homo, lumo, gfn2.gap)
91        }
92        DosMethod::Hf3c => {
93            let config = crate::hf::HfConfig::default();
94            let hf = crate::hf::solve_hf3c(elements, positions, &config)?;
95            // Estimate n_occ from element electron count
96            let total_e: usize = elements.iter().map(|&z| z as usize).sum();
97            let n_occ = total_e / 2;
98            let homo = if n_occ > 0 && n_occ <= hf.orbital_energies.len() {
99                hf.orbital_energies[n_occ - 1] * 27.2114 // Hartree → eV
100            } else {
101                0.0
102            };
103            let lumo = if n_occ < hf.orbital_energies.len() {
104                hf.orbital_energies[n_occ] * 27.2114
105            } else {
106                0.0
107            };
108            let gap = lumo - homo;
109            // Convert all orbital energies to eV
110            let oe_ev: Vec<f64> = hf.orbital_energies.iter().map(|e| e * 27.2114).collect();
111            (oe_ev, homo, lumo, gap)
112        }
113    };
114
115    // Compute DOS with Gaussian broadening
116    let dos = compute_dos(&orbital_energies, sigma, e_min, e_max, n_points);
117
118    Ok(MultiMethodDosResult {
119        energies: dos.energies,
120        total_dos: dos.total_dos,
121        method,
122        homo_energy,
123        lumo_energy,
124        gap,
125        orbital_energies,
126        sigma,
127    })
128}
129
130#[cfg(test)]
131mod tests {
132    use super::*;
133
134    #[test]
135    fn test_dos_method_eht() {
136        let elements = vec![8u8, 1, 1];
137        let positions = vec![
138            [0.0, 0.0, 0.117],
139            [0.0, 0.757, -0.469],
140            [0.0, -0.757, -0.469],
141        ];
142        let result =
143            compute_dos_multimethod(&elements, &positions, DosMethod::Eht, 0.3, -30.0, 5.0, 100);
144        assert!(result.is_ok());
145        let r = result.unwrap();
146        assert_eq!(r.energies.len(), 100);
147        assert!(r.gap > 0.0);
148    }
149}
sci_form/dos/multi_method.rs

sci_form/dos/
multi_method.rs
