I don't think so. But this stuff is always in flux. I see irony as constructive - it intends to produce something. In the case of the author, writing from an ironic perspective was the best way to describe a feeling and emotion that would have been hard, if impossible, to capture otherwise.

Sarcasm is entirely destructive. It isn't comedy, and it isn't irony. I'm pigeonholing it into a very tight definition, but when sarcasm is used, it tends to be used as a way to put the person using it on a higher pedestal than whomever the sarcasm is directed at. I'm not sure if that makes sense, but think of times when someone acts in a sarcastic manner. It usually isn't funny, and it doesn't communicate a feeling, it's just meant to make a witty or kitschy point that is meant to bring the subject of the sarcasm down and elevate the person who is using sarcasm, his or her feeling of self worth.

The OED defines sarcasm as 'a sharp, bitter, or cutting expression or remark; a bitter gibe or taunt'. Irony is often used in a sarcastic remark, but it's generally the cheap sort of irony - 'Well done, genius' in response to a stupid error - rather than the more literary sort, which when particularly well-developed we call satire.

IMO sarcasm is a form of irony that's brief and especially cutting.