Angular momentum form of Verlet algorithm for rigid molecules

作者：Hiyama Miyabi^*; Kinjo Tomoyuki; Hyodo Shi aki

来源：Journal of the Physical Society of Japan, 2008, 77(6): 064001.

DOI：10.1143/JPSJ.77.064001

• molecular dynamics simulation
• Verlet algorithm
• rigid molecules
• angular momentum form
• quaternion representation
• constraint by Lagrange's method of undetermined multipliers

A new simple algorithm is presented for solving the equations of motion for rigid molecules. These equations are integrated using a Verlet framework in the angular momentum form. This simple algorithm is named "the angular momentum Verlet algorithm". For obtaining a high accuracy in molecular dynamics (MD) simulations, we introduce the scaling method with the constraint by Lagrange's method of undetermined multipliers. The results of MD simulations for carbon tetrachloride using the angular momentum Verlet algorithm are reported. The relative total energy fluctuations for carbon tetrachloride using the angular momentum Verlet algorithm are compared with those using the standard leap-frog and Gear predictor-corrector algorithms. The energy drift using the angular momentum Verlet algorithm is smaller than that using the leap-frog or Gear predictor-corrector algorithm, particularly for large time intervals. The MD simulations for AX(n)Y(4-n)-type models having different moments of inertia are also carried out to investigate the effects of the angular momentum Verlet algorithm for molecules with different symmetries. We found that the time integrations for the model with the largest moment of inertia are stable. The scaling method with the constraint by Lagrange's method of undetermined multipliers in the angular momentum Verlet algorithm is effective in obtaining a smaller energy drift, particularly for large time intervals.

• 出版日期2008-6