Possible reasons:
(1) You didn't put density1.cub to VMD default folder (boot up VMD and input "dir", you will see all files in VMD default folder)
(2) The .cub file was not successfully generated. You can check file size.
BTW: VMD 1.9.3 should be used.
Hi, I am analyzing my ESP .fch output file from Gaussian. When i put "pt" command in the VMD prompt, it shows ESP. However when i put "iso" command in the VMD command promt, it shows "Could not read file density1.cub". What's the possible reason of this problem?