The probability of the occurrence of a transition between two quantum states of an atom, nucleus, electron, etc.
 Example sentencesExamples
-  The calculation of the propagation of the proton is based on the transition probability and probability density of the proton at each site along the trajectory.
 -  Probabilities for paternal haplotypes as functions of the transition probability t
 -  The ion flux at each step along the channel is a product of two terms: the transition probability between consecutive sites and the local probability density of the particles.
 -  We tried to substitute an amino acid at each site of the root sequence by generating a random number with the weight of the transition probability matrix between amino acids.
 -  The fastest rate constant used has a transition probability of only 0.03 during any given interval.