Molecular Deceleration is the ability to slow down the molecules of people or objects so that they move in slow motion like state. This is a weaker form of molecular immobilization, but could be seen as a more controlled version of it. It is an advancement of telekinesis.
This power has a limitation shown by Alec. Callie used her elemental ball on Nina, but Alec used his molecular deceleration on the elemental ball with one hand, but it was too much power to channel. When he used two hands, he only slowed the ball down slightly and very little.
Also, Alec combined his molecular deceleration with Matthew's immobilization power to use against a werewolf in his werewolf form. The two powers combined only made the werewolf decelerate slightly.
Alec was also shown to be able to use his telekinesis power by slowing down the molecules of something even more than his deceleration power can to cause immobilization. He is also the only user of this power to keep the deceleration power for a long time and was also able to use his telekinesis power to expand the effects and range of the deceleration power.