In 2001 a breakthrough is recorded in laser history when the barrier of femtoseconds (1fs=10-15 s, i.e., thousand times shorter than a millionth of a millionth of a second) was broken in the pulse duration with the obtention of the first pulsed lasers with durations of some hundreds of attoseconds (1 as= 10-18 s, thousand times shorter than a femtosecond). This has created the 'attophysics' field where the prototype of basic reaction is the ionization of atoms and molecules by 'attopulses' in the presence of a near infrared laser (NIR).
As the characteristic orbiting time of electrons in atoms and molecules belongs to the attosecond domain, one of the goals of attophysics is the control of the chemical reactivity. We give a simple example of this in this theoretical work published in Physical Review A (Phys. Rev. A, 90, 053414 (2014)). Through constructive or destructive interferences, (b) and (d), produced by varying the delay t0 between the attopulse and the NIR, one can control the electron emission from a H2+ molecule (that would normally occur in a symmetric way) giving place to electron emission in the up (a) or down (c) direction.

Interferences and asymmetries in laser-assisted photoionization of diatomic molecules
Diego I. R. Boll & Omar A. Fojón
Physical Review A 90 053414 (2014)
http://journals.aps.org/pra/abstract/10.1103/PhysRevA.90.053414