# Deer 3p hard echo.m

Samples the spin echo in the three-pulse DEER experiment for the purposes of determining its precise location. This is necessary in high-spin elec- tron systems for which the echo might not be in the expected place.

                echo=deer_echo(spin_system,parameters,H,R,K)


Parameters:

     parameters.ex_prob   - probe pulse operator

     parameters.ex_pump   - pump pulse operator

     parameters.ta        - time between first and third pulse

     parameters.tb        - time between first and second pulse

     parameters.tc        - time interval to sample around the echo

     parameters.rho0      - initial condition

     parameters.nsteps    - number of sampling steps in tc interval

     parameters.coil      - detection state


Note: always run this experiment before simulating DEER traces. DEER spin echo can be very narrow and easy to miss.