# How to passivate the surface of ZnSe Quantum Dot and apply vacuum to it? [closed]

I have been trying to simulate ZnSe zinc blende quantum dots using Quantum Espresso and its GUI BURAI. But being a beginner I am a little confused about a few things:

1. How do I passivate the surface, am I supposed to make a new .cif file after deciding which substance I wanna use for passivation and what coordinates do I wanna place these atoms at.
2. Do I even need passivation? I am trying to obtain optical band gaps for now.
3. How do I apply vacuum to my quantum dot. This procedure is fairly simple for molecules but when I do the same for quantum dot(I have been trying to simulate one with 8 unit cells which make a bigger cube of sort, is this a correct way to make a quantum dot?) but when I do the same for a qd, the atoms which are there on the cubic lattice(Zn) also move with the surface hence destroying the bonds between them and ones on the inside(Se). How do I fix this??
Thanks and I am a bachelors student who has not had any proper course(except for DFT one from coursera) in this and any other addvice would be greatly appreciated.
• Do I have to make this sort of structure for spherical qd (The guy in the video uses VESTA to arrange his structure in a spherical formation )- youtube.com/watch?v=P7rSGJixin8&list=LL&index=1 Jun 3 '21 at 10:03
• So I made a structure let me know if this looks correct(I have also given an explanation) - drive.google.com/file/d/1KVK5y-JToyjLjw3qzgSLszFWemIjZE1J/… Jun 3 '21 at 13:36
• This question looks a little too broad and I think sections of it have been covered by your later posts. It may be best to close this question or narrow it down to one specific question.
– Tyberius
Jun 23 '21 at 21:37
• @Tyberius I will close it Jun 24 '21 at 19:31