You just reminded me of something I had overlooked! EXCELLENT point about Benedict Arnold, Malte! Now that I think about it, there ARE historic examples of Pichegru being something of a "glory seeker" as the term goes I think. In the Fall/Winter of 1793, Pichegru was in direct competition with a man by the name of Lazare Hoche (who you're probably familiar with) to become head of the Army of the Rhine. The French Convention promised that whoever could win the biggest victory first would become head of the Army of the Rhine. As it turned out, Hoche was this man, and since he had Robespierre's backing as well, he was named as head of the Army of the Rhine.
HOWEVER, this isn't where the story ends. Not even a few weeks after Hoche's grand victory at Wissembourg, he is suddenly arrested and thrown in prison, letting Pichegru step into the void in his place. It turns out that several high ranking officers (Pichegru being among them, as well as known associates of his), had all gotten together to report that Hoche was "planning something treasonous", and the fact that so many had reported it got Hoche thrown in jail. Now we know these reports to be false, because Hoche was probably the least traitorous of any of the French generals at the time. He later went on to defeat the royalist landings in Quiberon, and won one of the last battles of the War of the First Coalition before he died of disease. It seems rather clear that Pichegru lied about Hoche in order to secure command of the Army of the Rhine for himself, and this later catapulted him to prominence, as he went on to command the Army of the North afterward, for which he's most well known.
So right there, we know that Pichegru was at the very least a jealous and spiteful individual.
Now we come to 1794. France is planning a two pronged offensive into Belgium, with Jourdan attacking in the east and Pichegru leading the main attack in the west. However, Pichegru's offensive stalls at the Battle of Tournai, and what ends up happening? Jourdan goes on to defeat Prince Josias at the Battle of Fleurus, winning almost god like status from this (as it's one of the most well known battles of this war). Now this is only speculation, but Pichegru might have felt slighted by this, as HE was supposed to be the one making the main attack and conquering Belgium. He may have felt overshadowed by Jourdan, who was already very famous for his defeat of the Austrians in 1793 at Wattignies. Jourdan was a rising star, and Pichegru had somewhat stagnated.
Now Pichegru DID gain fame when he single handedly conquered the Netherlands later that year, bute there was almost no resistance or any big battles. The Dutch pretty much let the French in, as they saw them as liberators and welcomed the chance to start a republic of their own. We now arrive at 1795, the year of Pichegru's betrayal.
Pichegru and Jourdan were supposed to lead a two pronged offensive into Austria. Jourdan would attack from the north, and Pichegru would attack from the east via Mannheim. At this point, Pichegru captures Mannheim almost effortlessly, but remarks that he didn't expect to advance so rapidly. He then sits down, and does nothing. Jourdan tells him that they should be moving together, as they're part of the greater offensive, but Pichegru rejects the idea of a joint effort, and says they'll only be working separately. At this point, the French Republic is not paying it's soldiers very well, and many generals have to settle for promises of payment later on.
Now here's my guess (and keep in mind it's ONLY a guess), but if Pichegru is being offered quite a lot of money by Austria, and if he perhaps feels overshadowed by Jourdan, then maybe he rather liked the idea of abandoning Jourdan, and letting him get defeated so that he would become discredited. The failure of the French offensive in 1795 certainly delayed the war by at least a year, as they could have been well into Austria if the two armies had moved together as planned.
So you brought up an excellent point. We DO know as fact that Pichegru was spiteful, as evidenced by his getting Hoche removed. So perhaps he felt the same way about Jourdan, and since it was also known that he wasn't getting paid particularly well (and supposedly had an extravagant lifestyle, at least according to one of his aides), then perhaps the Austrian offer to betray his nation was just a bit too tempting to pass up. I'm glad you brought up the point about Benedict Arnold and envy, as I think that's a very valid point, and definitely relates to Pichegru in this instance, as we have evidence that he was prone to... rather hurtful bouts of envy. XD
Yes, the Revolution really did eat its children too. Robespierre is a highly interesting character. I think overall he wanted to do right, but he let his own fears and paranoia get the better of him, and his ideals far exceeded what the French people wanted. In the end, he saved France from everyone but himself, as I think the saying goes. XD