text: # -*- coding: utf-8 -*-
  """
  Created on Mon Nov  4 10:01:07 2019
  
  @author: BSWOOD9321
  """
  
  import numpy as np
  import matplotlib.pyplot as plt
  
  
  q=.0483
  E=-10
  K=q*E
  V0=-83
  x=-100
  dx=1e-3
  X=[x]
  PSI=[np.exp(K*np.abs(x))]
  dpsi=-(np.sign(x))*K*np.exp(K*np.abs(x))
  psi=np.exp(K*np.abs(x))
  a=2
  
  while x <=a:
      if np.abs(x)>a:
          V=0
      else:
          V=V0
          
      d2psi=(q*V+K**2)*np.exp(K*np.abs(x))
      dpsi=dpsi+d2psi*dx
      psi=psi+dpsi*dx
      
      PSI.append(psi)
      x=x+dx
      X.append(x)
      
  x1=100
  X1=[x1] 
  PSI1=[np.exp(K*np.abs(x))]
  dpsi1=-(np.sign(x))*K*np.exp(K*np.abs(x))
  psi1=np.exp(K*np.abs(x))   
  
  while x1 >=a:
      if np.abs(x1)>a:
          V=0
      else:
          V=V0
          
      d2psi1=(q*V+K**2)*np.exp(K*np.abs(x1))
      dpsi1=dpsi1+d2psi1*dx
      psi1=psi1+dpsi1*dx
      
      PSI1.append(psi1)
      x1=x1-dx
      X1.append(x1)   
      
      
  plt.plot(X,PSI)
  plt.plot(X1,PSI1)
  plt.xlim(-5,5)
  
  plt.show()
      
      
      
      
  