phonon-sed (pSED)

Official Resources

• Homepage: https://github.com/tyst3273/phonon-sed
• Source Repository: https://github.com/tyst3273/phonon-sed
• Documentation: Included manual.pdf
• License: Open Source

Overview

phonon-sed (pSED) is a Python code to calculate the phonon spectral energy density (SED) from molecular dynamics simulations. It uses the normal-mode-decomposition technique to extract phonon frequencies, lifetimes, and linewidths from MD trajectories.

Scientific domain: Phonon spectral analysis, molecular dynamics post-processing
Target user community: Researchers analyzing phonon properties from MD simulations

Theoretical Methods

• Spectral energy density (SED) method
• Normal mode decomposition
• Fourier transform of velocities
• Phonon frequency extraction
• Linewidth and lifetime analysis
• Temperature-dependent phonon properties

Capabilities (CRITICAL)

• Phonon spectral energy density calculation
• Frequency extraction from MD
• Phonon lifetime estimation
• Linewidth analysis
• Temperature-dependent properties
• Compatible with LAMMPS output
• Command-line interface (pSED)

Key Strengths

SED Method:

• Direct from MD trajectories
• Includes anharmonic effects
• Temperature-dependent
• No perturbation theory needed

MD Compatibility:

• Works with LAMMPS
• General trajectory format
• Post-processing tool
• Flexible input

Inputs & Outputs

• Input formats:

  • MD trajectory files
  • LAMMPS dump files
  • Structure information

• Output data types:

  • Spectral energy density
  • Phonon frequencies
  • Linewidths
  • Lifetimes

Interfaces & Ecosystem

• LAMMPS: Primary MD code support
• Python: Pure Python implementation
• Command-line: pSED executable

Advanced Features

• Normal mode decomposition: Phonon-resolved analysis
• Fourier transform: Velocity autocorrelation processing
• Temperature dependence: Finite-temperature phonon properties
• Linewidth extraction: Phonon lifetime analysis
• LAMMPS integration: Direct trajectory processing

Performance Characteristics

• Python-based: Moderate speed
• FFT-limited: Scales with trajectory length
• Memory: Depends on system size and trajectory

Computational Cost

• MD simulation: Dominant cost (external)
• SED calculation: Minutes to hours
• Depends on trajectory length and system size
• Long trajectories needed for frequency resolution

Best Practices

• Use sufficiently long MD trajectories (>100 ps)
• Equilibrate system before production run
• Check frequency resolution vs trajectory length
• Validate against harmonic phonon calculations
• Compare with experimental spectroscopy when available

Limitations & Known Constraints

• Requires long MD trajectories
• Computational cost for large systems
• Resolution depends on simulation time
• Classical MD limitations

Application Areas

• Anharmonic phonon analysis
• Temperature-dependent phonon properties
• Thermal transport studies
• Phonon lifetime extraction
• MD validation against experiment

Verification & Sources

Primary sources:

1. GitHub: https://github.com/tyst3273/phonon-sed
2. Based on: T. Sun et al., J. Appl. Phys. 117, 135104 (2015)

Confidence: VERIFIED

Verification status: ✅ VERIFIED

• Source code: OPEN (GitHub)
• Documentation: Manual included