Objection 1. It would seem that the damned will sometimes think of God. For one cannot hate a thing actually, except one think about it. Now the damned will hate God, as stated in the text of Sentent. iv, in the last Distinction. Therefore they will think of God sometimes.
Objection 2. Further, the damned will have remorse of conscience. But the conscience suffers remorse for deeds done against God. Therefore they will sometimes think of God.
On the contrary, Man's most perfect thoughts are those which are about God: whereas the damned will be in a state of the greatest imperfection. Therefore they will not think of God.
I answer that, one may think of God in two ways. First, in Himself and according to that which is proper to Him, namely that He is the fount of all goodness: and thus it is altogether impossible to think of Him without delight, so that the damned will by no means think of Him in this way. Secondly, according to something accidental as it were to Him in His effects, such as His punishments, and so forth, and in this respect the thought of God can bring sorrow, so that in this way the damned will think of God.
Reply to Objection 1. The damned do not hate God except because He punishes and forbids what is agreeable to their evil will: and consequently they will think of Him only as punishing and forbidding.
This suffices for the Reply to the Second Objection, since conscience will not have remorse for sin except as forbidden by the Divine commandment.
Source: Summa Theologica (New Advent)