At the prompt, "wavelength =", type in the wavelength of the wave in multiples of the lattice parameter a. For example, type 1 for a wavelength equal to a, type 2 for a wavelength equal to 2a, etc. The number you type must be an integer no smaller than 1 and no larger than 10.
At the next prompt, "branch (0=acoustic, 1=optical):", type in either 0 or 1 to see a wave in the acoustic or optical branch, respectively.
The program recognizes the following commands:
| S | Stop animation. Press any key to resume animation. |
| Q | Quit program. |
| ? | Help. These commands are listed. |