en passant capture

Can I do it here?

Yes

any idea on how to do it?

If you're talking about this game: Game 5639723 - en passant is not possible in that position. The idea of en passant is that if a pawn avoids being captured by a pawn by moving two squares for its first move, you can, if you choose, take it as if it had only moved one square. This is not the situation in that game.

Originally posted by madhavb
Can I do it here?

You can, but it's considered poor sportsmanship to do so.

I'm just kidding. 🙂 It's a perfectly legitimate chess move.

Essentially, if you have a pawn on your 5th rank and the other player moves a pawn on an adjacent file from his second rank to his 4th rank (i.e., jumping over the square at which your pawn could have made the capture), you can make the pawn capture as though the opposing pawn were on his third rank. This can only be done at the first opportunity, however.

If you think of the logic behind it, the rule becomes simple. Double pawn moves from the 2nd to 4th rank were meant to speed up the game by giving pawns a head start, not to enable pawns to jump ahead to avoid capture by other pawns. So, if the pawn tries to jump with a double move past where it could have been captured by another pawn, you can capture it anyway.

Originally posted by madhavb
Can I do it here?

If you mean can you do it on RHP, the answer is yes. Just make the appropriate pawn move.
If you are uncertain about the Law you will find the official FIDE wording in their website : -
http://www.fide.com/component/handbook/?id=32&view=category
L-CK on 'E.1.01A Laws of Chess', and then go to Article 3.7d.
"A pawn attacking a square crossed by an opponent's pawn wnich has advanced two squares in one move from it's original square may capture this opponent's pawn as though the latter had been moved only one square. This capture is only legal on the move following this advance and is called an 'en passant' capture."