These days it's hard to get published without a close collaboration between theory and experiment. Even in cases when it is evident what your STM/AFM/KPFM image is telling you, publishers will still insist on seeing a theoretical prediction. In these cases, where you "just need the theory", it is of particular importance to have a theoretician on hand.
So how do you get into this Nirvana of science - the theory-practice equilibrium? Well, there are a few things to keep in mind.
It's reciprocal - The theorists need you as badly as you need them. The pure theory papers don't usually get into the high-impact journals either. Think like dating. Although, as the experimentalist, you need to take the first step since you have the juicy piece of data.
It should be long-term - Or maybe you should even think of it as a marriage. All genuinely fruitful collaborations I know of spans years and only start to get really good at the decade mark.
It is all about trust - How do you know that your new urgent simulations really will get done in a few weeks as they say? Trust. How do you know they have tried everything as they say? Trust. If there is no trust, your simulations can quickly end at the bottom of a pile of more interesting tasks.
Don't take their nonsense - To build trust, you must understand what they are talking about at some level. And even when you have built trust your theoretician could be going out of his/her way to make life more complicated than needed. Theoreticians are always doing this. To avoid this, build your knowledge. Note the theory methods used last time you got good agreement with your experiments and do some light reading on it. And next time you plan a project, you will have some power to ask why the simulation methods you used last time suddenly aren't good enough.
Advance your partner - You must ensure that your partner is emphasized and promoted. Put them as the first author when they puzzled out the solution. Support their work at conferences. Remember, if they run out of funding you will lose your source. Show your loyalty.
Even then, when you have built a relationship over the years, it can break down quickly due to outside forces. My own partner in science for many years, Dr. Szymon Godlewski, is an excellent example of this. For three years he worked with me with patience, persistence, and loyalty with a great theoretician - who then lost funding for the project and had to do it on the side. Then he got me through an arranged union (EU project), and we had some beautiful papers together. But now I can't be quite as attentive to his needs because I have started a company. Ironically, a company designed to solve the problems that experimentalists like Szymon struggle with.
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