Resonance in the dynamics of chemical systems simulated by the implicit midpoint scheme

✍ Scribed by Margaret Mandziuk; Tamar Schlick

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 795 KB
• Volume: 237
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(95)00316-v

✦ Synopsis

The numerical behavior of the symplectic, implicit midpoint method with a wide range of integration timesteps is examined through an application to a diatomic molecule governed by a Morse potential. Our oscillator with a 12.6 fs period exhibits notable, integrator induced, timestep-(At) dependent resonances and we predict approximate values of At where they will occur. The particular case of a third-order resonance (At ~ 7 fs here) leads to instability, and higher-order resonances (n = 4, 5) to large energetic fluctuations and/or corrupted phase diagrams. Significantly, for At > 10 fs the energy errors remain bound.