| Intermolecular interactions play a crucial role in biological systems,planetary atmospheres,and interstellar gas and have attracted considerable attention from both theoretical and experimental researchers.Van der Waals（vd W）molecules are weakly bound complexes of atoms or molecules held together by intermolecular attractions and are the prototype systems for investigating intermolecular interactions.High-resolution laser spectroscopy is one of the most important experimental tools to investigate the properties of vd W complexes.Meanwhile,constructing the intermolecular potential energy surface and solving the Schrodinger equation of the nuclear motion of vd W system,most of the information about the system can be obtained theoretically,which is of great significance for interpreting and verifying the data of molecular spectrum experiment and further exploring the nature of the interactions between molecules.It is extremely important to develop efficient and accurate quantum dynamical programs for the theoretical study of vd W systems.The exact solution of the bound state equation for the vd W system requires enormous computational effort.Since the number of ab initio points and basis functions grows exponentially with the number of degrees of freedom,so does the computational time,memory,and additional resources.The following two parts are the main content of the article:1.Using parallel computing technology to reconstruct the quantum dynamics program,which greatly improves the operation efficiency of the program.Aiming at the theoretical study of vd W systems,we develop parallel programs for solving bound states of vd W systems using MPI and Open MP parallel computing methods.Moreover,the reliability of the program is verified for Ar-Na Cl,（HF）2,Xe-H2O,respectively.The calculation results for(HF2) show that with the increase of computation,the speed ratio of 4-node MPI parallel program compared with serial program is 1.67,1.68,1.8,1.9,2.03.The 8-node MPI parallel program has a speed ratio of 1.68,1.85,2.47,2.48,2.65 compared to the serial program.It has been shown that the efficiency of parallel programs is highly enhanced in the presence of large amounts of computation.This scheme can make full use of computer resources,greatly saving the running time of the program and facilitating the investigation of more complex vd W systems.At the same time,by means of static compilation,the built-in MPICH static library in the program solves the problem of incompatible compilation of MPI program in different platform environment,realizes the program’s"black box function",makes the program can be used across platforms,and improves the program’s usability.2.This paper proposes a new method of constructing high-precision van der Waals complexes potential energy surfaces using neural network,which has high fitting accuracy.In this work,the symmetry-adapted rotational basis functions in the bound state calculations are used as descriptors to maintain the full symmetry of the vd W complex.These descriptors are effective because these rotational basis functions are orthogonal and the number of them can be well tuned.The descriptors for the five most common types of vd W complexes are discussed,including atom-linear molecule,atom-nonlinear molecule,linear-linear molecule,linear-nonlinear molecule,and nonlinear-nonlinear molecule.To evaluate the performance of these descriptors,PESs for four complexes are constructed and analyzed.The total RMSE of the fitted PESs are 0.025 cm-1 for Ar-Na Cl complex,0.061 cm-1 for Ar-SO2 complex,0.015 cm-1for H2O-H complex,0.26 cm-1 for N2-OCS complex,and 0.36 cm-1 for N2-H2O complex,respectively.The small RMSE values demonstrate the power of our NN-PES method in constructing accurate PESs for vd W complexes,and perform well for molecular systems with strong specificity. |
