# rotframe.m

Rotating frame transformation with respect to specified spins to specified order in perturbation theory (https://doi.org/10.1063/1.4928978).

## Contents

## Syntax

H=rotframe(spin_system,H0,H,isotope,order)

## Arguments

H0 - carrier Hamiltonian with respect to which the rotating frame transformation is to be done H - laboratory frame Hamiltonian H0+H1 that is to be transformed into the rotating frame isotope - string, such as '1H', specifying the spins with respect to which the transformation is being computed order - perturbation theory order in the rotating frame transformation, this may be inf

## Outputs

H - rotating frame Hamiltonian

## Notes

The auxiliary matrix method is massively faster than either commutator series or diagonalisation.

## See also

intrep.m, average.m, dirdiff.m, propagator.m, equilibrium.m

*Version 2.2, authors: Ilya Kuprov*