I wouldn't have an idea to convey this in game any more than it is now, but I've gathered this.
Grav beam deals no damage, like other grav beams. Damage is physics based, determined by collision speed, Mass of both units. Bounce is based (soley) on the mid points of both units. The collision damage is like fall damage.
Jump causes a weapon like explosion.
The way the game handles jumps, btw, is important. Units follow a pre-determined path, moving at a pre-approval defined speed, in a forced way. The only way to stop a jump is unit death, impulse has no effect on units with jumpjets/jumplegs(which are for these porpus indistinguishable) and jumping units movement is set to 0 on landing.