Computational chemistry singlet carbenes

The transient decays at the same rate as cyclic ketenimine K is formed," implying that the newly detected transient is singlet phenylnitrene. The assignment was secured with the aid of computational chemistry" and by studying the temperature dependence of the kinetics. " In 1986 we guessed that the ISC rate constant of singlet phenylnitrene would resemble the same rate constants as those of aryl carbenes, which were known at that... 

Carbene structures and properties can now be computed with chemical accuracy , despite the difficulties associated with multi-reference species such as singlet carbenes. This is particularly encouraging since the determination of singlet-triplet energy separations and accurate structures of carbenes, which very often are, at best, fleetingly observable intermediates, is extremely difficult experimentally. Transition structures also can be computed apparently with good accuracy and complement experimental studies of the reactions as well as the complex rearrangements commonly found in carbene chemistry. 

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