Ultrafast photodissociation dynamics of electronically excited CF2I2 molecules

Using the femtosecond pump–probe technique in combination with REMPI–TOF mass spectrometry we investigated the photodissociation dynamics of CF2I2. After excitation by the 267 nm pump pulse (probe pulse 400 nm), a relaxation process with a time constant τ≈30 fs leads to an intermediate state of CF2I2, which subsequently dissociates with τ≈100 fs into CF2, I and I2. Within experimental error (±30 fs) these fragments are formed with the same rate. Since in addition no evidence of a transient species CF2I was found, a concerted reaction mechanism is proposed for this ultrafast dissociation process.