ИСТИНА

Calculations of interatomic vibrational amplitudes and corrections in gas electron diffraction are normally done. To obtain a semi-experimental equilibrium structure for any molecule using conventional methodics a cubic force field is required[1,2]. However, calculations of cubic force fields for large molecular systems are computationally very expensive and can be too long. Another way for computation of required in GED parameters from molecular dynamics (MD) trajectories has been previously proposed[3,4]. Unfortunately, classical MD simulations lack for quantum effects[3,4] and can be affected by the “flying ice cube effect”[5]. We have developed computationally effective model for approximation of these effects and correction of parameters obtained from MD simulations. A new program Qassandra has been written to implement a corresponding computational procedure. A series of calculations have been carried out to show the applicability of our model on test objects of different sizes. Results have been compared with those obtained by conventional methods. [1] V. Sipachev, Struct. Chem. 2000, 11, 167. [2] I. Kochikov, Yu. Tarasov, G. Kuramshina, V. Spiridonov, A. Yagola, T. Strand, J. Mol. Struct. 1998, 445, 243. [3] D. Wann, R. Less, F. Rataboul, Ph. McCaffrey, A. Reilly, H. Robertson, P. Lickiss, D. Rankin, Organometallics 2008, 27, 4183. [4] D. Wann, A. Zakharov, A. Reilly, P. McCaffrey, D. Rankin, J. Phys. Chem. A 2009, 113, 9511. [5] S. Harvey, R. Tan, Th. Cheatham III, J. Comput. Chem. 1998, 19, 726.