The phrase "already dissipated" is correct and usable in written English.
It can be used to describe something that has dispersed or faded away prior to the current moment.
Example: "The tension in the room had already dissipated by the time the meeting started."
Alternatives: "already faded" or "already dispersed".
The deep plumes have already dissipated, apparently eaten by the Gulf's oil-adapted microbes.
I quickly waved my hands in a move I'd learned in science class, trying to cup the lost aroma, but it had already dissipated.
EPA officials said the shocking orange plume has already dissipated and that the leading edge of the contamination cannot be seen in the downstream stretches of the San Juan River or Lake Powell.
We complied but the party had already dissipated.
If UCPs were active, then the addition of DNP would make no difference in the temperature rise because the proton gradient was already dissipated.
The events which precipitated the Priestley Riots came less than a month after the attempted flight and arrest of the French Royal family, and at a point when much of the early promise of the Revolution had already dissipated.
True, the appearance that Cheney was running things was already dissipating by the time I sat down with him.
A gulp of outside air came in with her, hot enough to reach Rose in the living room but already dissipating, a flame thankfully snuffed.
Obama's popularity, which is the currency any President needs to be effective, is already dissipating (see this Wall Street Journal piece by Doug Schoen and Scott Rasmussen, for instance), and key Democrats in the Senate have reacted tepidly to his budget, arguing that the President may be asking that body to do too much too fast.
There are very close links and very close ties". The other "negative stuff ' - the perception that al-Jazeera is a mouthpiece for terrorists, the baseless rumour that it broadcast beheadings - is already dissipating and will drift away as the scales drop from western eyes, Phillips confidently predicts.
From the numbers Wells is giving -- that a full third of new sign-ups are returning customers -- it seems like that "negative PR swirl" is already dissipating.
