The paper has been under peer review at Physica Scripta (IOP) since March 25. The reviewers will decide what stays and what's trimmed. You're reading a preprint, not the final version. The tone in the architecture sections reflects the scope of the claim — reviewers may ask me to moderate it, and I will. The core physics (Sections 2–3) is standard computational chemistry: DFT, transition state optimization, CCSD(T) validation. Those sections read like any other ab initio paper.

Ah, that's interesting. Different countries can be a fair reason I suppose.

3 PhDs is quite some dedication to science, given that a PhD student life is neither that of plenty nor leisure.

What's so special about specifically the PhD student experience that isn't accessible once you have the PhD?

My experience has been that research became much more fulfilling after finishing my PhD. I got more research independence, the level of work I was expected to do increased, and as a bonus, my salary almost tripled. It was like having the world open up, and starting to really experience being a scientist without my PI protecting me.

I was curious about their decisions because if you're taking on the opportunity cost of a PhD, it's probably because you enjoy research, but if you enjoy research, you wouldn't keep going back to the starting point. So, without additional context, it seemed like they just wanted the credentials.

Their explanation about different countries is potentially an explanation, it's not like I'm asking them to lay out all their personal circumstances behind the decision.