Official Resources
- Homepage: https://www.lct.jussieu.fr/pagesperso/silvi/topmod_english.html
- Documentation: https://www.lct.jussieu.fr/pagesperso/fuster/TOPMOD/topmod-manual.pdf
- Source: Available from homepage
- License: Academic use
Overview
TopMod is a FORTRAN package for topological analysis of the Electron Localization Function (ELF). It calculates the ELF on a 3D grid, assigns basins, and computes basin populations and their variances. This enables quantitative analysis of chemical bonding in terms of core, bonding, and lone pair basins.
Scientific domain: ELF topology, chemical bonding, electron localization
Target user community: Researchers studying chemical bonding through electron localization
Theoretical Methods
- Electron Localization Function (ELF)
- Topological analysis (gradient field)
- Basin assignment and integration
- Population and variance calculation
- Synaptic order classification
Capabilities (CRITICAL)
- ELF Calculation: 3D grid evaluation
- Basin Analysis: Core, bonding, lone pair basins
- Population: Basin electron populations
- Variance: Population fluctuation analysis
- Synaptic Order: Basin connectivity
- Visualization: Basin boundaries
Sources: TopMod documentation, Silvi group publications
Key Strengths
ELF Specialization:
- Complete ELF analysis
- Basin classification
- Population statistics
- Quantitative bonding
Established Method:
- Well-validated
- Extensive literature
- Standard methodology
- Benchmark results
Gaussian Compatible:
- Direct wfn input
- Standard format support
- Easy workflow
- Gaussian 92-16
Inputs & Outputs
-
Input formats:
- Gaussian wfn files
- Standard wavefunction format
-
Output data types:
- ELF values on grid
- Basin assignments
- Population values
- Variance statistics
Installation
# Download from homepage
tar -xvf topmod.tar
cd topmod
make
Usage Examples
# Prepare input file
# Run TopMod
./topmod < input.dat
# Input file format:
molecule.wfn # wavefunction file
80 80 80 # grid points
0.1 # step size
Performance Characteristics
- Speed: Efficient grid evaluation
- Memory: Depends on grid size
- Accuracy: Well-established method
Limitations & Known Constraints
- FORTRAN: Older codebase
- Grid-based: Resolution dependent
- Documentation: Limited online resources
- Visualization: Requires external tools
Comparison with Other Tools
- vs Multiwfn: TopMod specialized ELF, Multiwfn broader
- vs Critic2: TopMod ELF focus, Critic2 general topology
- vs DGrid: Different ELF implementations
- Unique strength: Original ELF topology implementation
Application Areas
- Chemical bond characterization
- Lone pair identification
- Hypervalent bonding
- Metallic bonding analysis
- Electron pair domains
Best Practices
- Use sufficient grid resolution
- Verify basin connectivity
- Compare populations with expectations
- Cross-validate with other methods
Community and Support
- LCT Paris group
- Academic distribution
- Published methodology
- Bernard Silvi (developer)
Verification & Sources
Primary sources:
- Homepage: https://www.lct.jussieu.fr/pagesperso/silvi/topmod_english.html
- S. Noury et al., Comput. Chem. 23, 597 (1999)
- B. Silvi, A. Savin, Nature 371, 683 (1994)
Confidence: VERIFIED - Established academic software
Verification status: ✅ VERIFIED
- Homepage: ACCESSIBLE
- Documentation: AVAILABLE (PDF)
- Source code: ACADEMIC distribution
- Developer: Bernard Silvi (LCT Paris)
- Academic citations: Well-cited
- Method: ELF topology analysis