To get the Dark Matter for Shockwave Pulsar you need to get Siren to Lv. 100 then use Tool-RF with 100 Curse Spikes.

The full list of Quistis' Limit Breaks is;

Laser Eye (already learnt)
Ultra Waves (Spider's Web)
Electrocute (Coral Fragment)
Lv? Death (Curse Spike)
Degenerator (Black Hole)
Aqua Breath (Water Crystal)
Micro Missiles (Missile)
Acid (Mystery Fluid)
Gatling Gun (Running Fire)
Fire Breath (Inferno Fang)
Bad Breath (Malboro Tentacle)
White Wind (Whisper)
Homing Laser (Laser Cannon)
Mighty Guard (Barrier)
Shockwave Pulsar (Dark Matter)
Ray-Bomb (Power Generator)