https://www.newadvent.org/cathen/01142c.htm
Aquinas is good enough for me.
This is, then, one pre-V2 source that claims laity can adjure demons. Nevertheless, it goes farther than Ripperger does, with the latter stating that it may only be done in situations where a layman has authority over the person being afflicted by the demon, and this article puts no such restriction on it.
But, no, it's not St. Thomas, but, rather, someone's interpretation of St. Thomas, that is "good enough for [you]", as there's no citation anywhere of what St. Thomas actually wrote. Maybe we should actually read what St. Thomas wrote, just as Ripperger needed to actually read what St. Alphonsus wrote. You can find pre-V2 sources that promote every error of Vatican II, and there is in fact some heresy in it. So, it would behoove you to go track down what St. Thomas wrote instead of taking a sources word for it (as you did with Ripperger, and you were misled).
This article, just like Ripperger did, makes only the distinction between private/solemn, and ignores most of what St. Alphonsus ACTUALLY wrote on the subject.
St. Alphonsus was clear. There are two distinctions at work:
1) solemn vs. private
2) imperative vs. deprecatory
These are not to be conflated. In fact, there's a lengthy discussion in St. Alphonsus about whether an Exorcist (while acting in a solemn capacity) would commit a mortal sin if engaging in superfluous interrogation of the demon(s). All agreed that it would be, if done regularly. Then the question turns to, would it be a mortal sin even to just ask one or two such superfluous questions? St. Alphonsus cites one authority who said it would be, asserting that it would be in the nature of a deprecatory adjuration (since the line of questioning would be nowhere in the Catholic Ritual, and therefore it would lack the necessary authority to render it imperative). St. Alphonsus does not dismiss the opinion but states that he considered it more probable that it would only be a venial sin in that the question could still be presented with an imperative intent, even if not specifically and explicitly sanctioned by the Church's authority in so many words, presumably because the minister had the authority generally, vs. specifically only to do what's prescribed in the Rite). In either case, it's considered sinful.
But here's the key point. Even in a solemn exorcism, the minister would commit mortal sin by engaging in deprecatory adjuration of the demon ... in other words, demonstrating once again that these are two separate distinctions.
St. Alphonsus, then, clearly lays out that that no one, whether a minister or not, whether during the performance of a solemn rite or not, is permitted to engage in deprecatory adjuration of demons.
Then, in describing "imperative" adjuration, he states that imperative adjuration ONLY (
tantum) applies when 1) the adjurer has direct authority over a subordinate or 2) by an Exorcist over demons. Period. He makes no other allowances for imperative adjuration, such as Ripperger's invented "you can do it if the person afflicted is under your authority." In fact, the New Advent article cited above puts no such restriction on it, so by all means start up your own Lay Exorcist Deliverance Ministry.
So, you go right ahead, buddy, and start exorcising demons. That article cites the example of the Jєωs who tried to exorcize demons "in the name of Jesus" and were immediately turned on and possessed by the demons. So you go ahead and play with demons, as Ripperger suggests, rather than having confidence in Our Lady, and the Angels, who can infallibly expel them, rather than relying on your own powers (that you implicitly hold are superior to those of Our Lady). You call yourself "HolyAngels" here but then behave as if you have no confidence in said Angels, but instead adopt the attitude of "if you want it done right, you need to do it yourself." Even NewAdvent cautions that any vainglory or pride in attempting to exorcise demons can have disastrous consequences. So the minute you get up there and think you're a tough guy taking on demons and reveling even slightly in your "powers" and "authority," it takes but a momentary lapse along those lines before you're having to call an Exorcist to exorcise the demons from you. Those, however, acting with real authority, i.e. Exorcists, to not pretend as if they had some personal authority over the demons, but recognize that they are acting with the authority of the Church. That is very real and practical reason that the Church requires (and St. Alphonsus teaches) that one has to have explicit authority from the Church to engage the demons.
But, let's go ahead and find what St. Thomas actually wrote instead of this writer's interpretation of it; he's already conflating private/solemn with laity/ministers.
Alas, we'll have to dig it up because, despite the article claiming that St. Thomas wrote this, there's no actual citation to St. Thomas, just some manualists and St. Alphonsus ... and none of them is actually directly quoted. Nor are the references helpful, just say "Book I" or "Book V" of this or that theologian, and no specific passages.