LAUSR

Significance Modeling water’s dynamic bond network and accurately predicting physical properties is challenging. As a result, small water clusters are crucial templates to understand hydrogen bonding at a simpler level. Unfortunately, such clusters can only be studied under cryogenic conditions and often with uncontrolled charge or size. Here, we introduce a technique to trap and analyze neutral water clusters in ambient conditions, by encapsulating them in barrel-shaped molecules (cucurbiturils) and measuring them with Raman spectroscopy. We observe a confined water dimer and demonstrate facile tuning of its environment and even isotopic composition, paving the way for probing ambient water cluster dynamics in situations difficult to access in previous experiments.