Water Resonance
Oxygen Resonance
Hydrogen Resonance
Water has three different vibrational modes - there are vibrational frequencies associated with these, but these are not really oscillations like a mass on a spring which we would be familiar with seeing. The webpage you link has some 'vibrational frequencies' of different molcules and notes they are significantly higher than the 2.45 GHz microwave range.
So water can be excited rotationally by 2.45 GHz - the rotational behaviour of water as single molecules in the gas phase is very complicated. Water is an 'asymmetric rotor', which turns out to be the hardest to understand. In liquid water the rotation is further complicated by collisions between adjacent molecules.
2.45 GHz is used is because it is a standard frequency that is allowed and doesn't interfere with licensed communications systems, part of the 2.4 GHz
https://en.m.wikipedia.org/wiki/Electromagnetic_absorption_by_water
https://en.m.wikipedia.org/wiki/Terahertz_radiation