Both SPECIFIC and PARTICULAR can be used for something unique or special about a person, place or thing.
The word SPECIFIC is used when something is clearly detectable or NOTICEABLE, perhaps measurable.
For example, you could say: "this drug has a specific effect on the disease".
In other words, it has been noticed by scientists that the drug has these characteristics.
You could say: "this specific heat is required to melt the sugar ".
In other words, there is a detectable and limited temperature required.
The word PARTICULAR is used WHEN YOU SINGLE SOMETHING OUT among may.
For example, you could say: "I want a particular book from the library".
In other words, you want one book among many others.
You could say: "She is the particular person I had in mind for the job".
In other words, she was one among many.
Hope this helps