Function analyze_reaction_path

Source

pub fn analyze_reaction_path(geometries: &[Geometry]) -> PathStatistics

Expand description

Analyzes a reaction path and computes comprehensive statistical information.

This function performs detailed analysis of a reaction path, calculating various metrics that characterize the path quality, length, and properties. It’s essential for understanding reaction mechanisms and validating path optimization results.

§Analysis Components

§Path Length Calculation

Computes the total arc length along the reaction path:

L_total = Σᵢ₌₁ⁿ⁻¹ RMSD(Rᵢ₊₁, Rᵢ)

This represents the total “distance” traveled in configuration space from reactant to product.

§Geometric Metrics

Number of images: Total path resolution
Average spacing: Mean distance between consecutive images
Path smoothness: Variation in inter-image distances

§Energy Analysis (Future Extension)

The framework supports energy analysis:

Barrier heights: Maximum energy along path
Reaction energy: Energy difference between endpoints
Energy profile: Complete energy vs. reaction coordinate

§Arguments

geometries - Array of molecular geometries representing the reaction path

§Returns

Returns a PathStatistics struct containing:

path_length: Total path length in coordinate space
num_points: Number of geometries in the path
energies: Energy values (currently empty, for future use)
coordinates: Reaction coordinate values (currently empty, for future use)

§Path Length Interpretation

§Physical Meaning

The path length represents the “effort” required to transform the reactant into the product through the specific pathway:

Short paths: Direct, efficient transformations
Long paths: Complex, multi-step mechanisms
Very long paths: Potentially unphysical or poorly optimized

§Typical Values

Simple reactions: 1-5 Angstrom total path length
Complex rearrangements: 5-20 Angstrom total path length
Conformational changes: 2-10 Angstrom total path length

§Applications

§Path Quality Assessment

Resolution check: Ensure adequate number of images
Smoothness evaluation: Identify poorly optimized regions
Convergence monitoring: Track path changes during optimization

§Mechanism Analysis

Pathway comparison: Compare different reaction routes
Bottleneck identification: Find regions requiring more images
Coordinate selection: Choose appropriate reaction coordinates

§Method Validation

Algorithm comparison: Evaluate different path optimization methods
Parameter tuning: Optimize NEB spring constants and convergence criteria
Benchmark studies: Compare with experimental or high-level theoretical results

§Examples

use omecp::reaction_path::analyze_reaction_path;

// Analyze an optimized reaction path
let stats = analyze_reaction_path(&optimized_path);

println!("Path analysis:");
println!("  Total length: {:.3} Angstrom", stats.path_length);
println!("  Number of images: {}", stats.num_points);
println!("  Average spacing: {:.3} Angstrom",
         stats.path_length / (stats.num_points - 1) as f64);

§Future Extensions

§Energy Integration

When energy data becomes available:

// Future capability
if !stats.energies.is_empty() {
    let barrier_height = stats.energies.iter().fold(0.0, |a, &b| a.max(b));
    println!("Activation barrier: {:.2} kcal/mol", barrier_height * 627.5);
}

§Advanced Metrics

Path curvature: Measure of path deviation from straight line
Intrinsic reaction coordinate: Arc length parameterization
Turning points: Identify regions of high curvature
Bottleneck analysis: Locate transition state regions

analyze_reaction_path

Function analyze_reaction_path Copy item path