particlesInput

2 atoms
2 atom types
-0.0005 0.0018 xlo xhi 
-0.0005 0.0005 ylo yhi 
-0.0005 0.0005 zlo zhi 

Atoms

1 1 200e-6 2500 0.0  0.0 0.0  
2 2 400e-6 2500 1300e-6 0.0 0.0  

Velocities 

1  50000e-6 0.0 0.0 0.0 0.0 0.0 
2 -50000e-6 0.0 0.0 0.0 0.0 0.0