分子动力学：2D中粒子的轨迹

Question

我试图弄清楚如何计算粒子的轨迹。

我很难搞清楚从哪里开始。

下图是我想要的样子，因为后来，我想用maxwells分布方程绘制这些轨迹的速度和速度分布。

到目前为止，这是我的代码

import numpy as np
import matplotlib.pyplot as plt
import time

from numpy.random import rand
from scipy.linalg import norm

def F(pos,vel,n,nsteps):
for tsteps in range(nsteps-1):
    i=0
    vel[i] = vel[i]
    pos[i] = pos[i] + vel[i] * dt
    if pos[i,0] > L:
        pos[i,0] = pos[i,0] - L
    elif pos[i,0] < 0:
        pos[i,0] = pos[i,0] + L
    elif pos[i,1] > L:
        pos[i,1] = pos[i,1] - L
    elif pos[i,1] < 0:
        pos[i,1] = pos[i,1] + L
        vel[i,1] *= -1
    if tsteps%1 == 0:
        plt.scatter(pos[i,0],pos[i,1],color="b",s=2)
        plt.draw()
n=1
L=10
nsteps=200
dt=0.28   
pos=np.zeros([n,2])
vel=np.zeros([n,2])


plt.figure(figsize=[8,8])
plt.axis([0,L,0,L])
plt.ion()

plt.show()

pos_init = np.array([0,0])
vel_init = np.array([-1,-0.31456])

pos[0,:] = pos_init[:]
vel[0,:] = vel_init[:]

t0= time.time()
F(pos,vel,n,nsteps)
print("execution time = " , time.time()- t0)