def distance_to(atom)
		Math.sqrt((self.x - atom.x)**2 + (self.y - atom.y)**2 + (self.z - atom.z)**2)
	end
def distance_to(atom)
		Math.sqrt((self.x - atom.x)**2 + (self.y - atom.y)**2 + (self.z - atom.z)**2)
	end
Return the distance to another atom