I don't remember seeing any charts, but when I ran my 3.5 campaign, I awarded the same amount of xps to my players when they had a role-playing encounter the same as if they had defeated a creature of the same level as the encounter. Did something similar for puzzles too!
There's no reason why you couldn't award xps based off of a particular encounter level according to how the players handled something you placed in front of them. If they were successful, you give them full xps, if they were partially successful, you give them partial xp, etc.
I'd just make sure that they knew they didn't have to kill/defeat everything they came across to gain xps.