deer_3p_soft_deer.m

Three-pulse DEER/PELDOR pulse sequence. The sequence uses soft pulses computed with the Fokker-Planck formalism.

Syntax

echo_stack=deer_3p_soft_deer(spin_system,parameters,H,R,K)

Arguments

parameters.pulse_frq - frequencies for the three

                           pulses, Hz

   parameters.pulse_pwr  - power levels for the three
                           pulses, rad/s

   parameters.pulse_dur  - durations for the three
                           pulses, seconds

   parameters.pulse_phi  - initial phases for the three
                           pulses, radians

   parameters.pulse_rnk  - Fokker-Planck ranks for the
                           three pulses

   parameters.p1_p3_gap  - time between the first and the
                           third pulses, seconds

   parameters.p2_nsteps  - number of second pulse posi-
                           tions in the interval between
                           the first and the third pulse

   parameters.echo_time  - time to sample around the ex-
                           pected echo position

   parameters.echo_npts  - number of points in the echo
                           discretization

   parameters.rho0       - initial state

   parameters.coil       - detection state

   parameters.spins      - irradiated spins, normally {'E'}

   parameters.method     - soft puse propagation method,
                           'expv' for Krylov propagation,
                           'expm' for exponential propa-
                           gation, 'evolution' for Spin-
                           ach evolution function

   H  - Hamiltonian matrix, received from context function

   R  - relaxation superoperator, received from context function

   K  - kinetics superoperator, received from context function

Outputs

echo_stack - DEER echo stack, a matrix with p2_nsteps echoes

                 with echo_npts points each

Note: for the method, start with 'expm', change to 'expv' if the
      calculation runs out of memory, and use 'evolution' as the
      last resort.

Note: simulated echoes tend to be sharp and hard to catch becau-
      se simulation does not have distributions in experimental
      parameters. Fourier transforming the echo prior to integ-
      ration is recommended.

Note: the time in the DEER trace refers to the second pulse inser-
      tion point, after end of the first pulse.

ilya.kuprov@weizmann.ac.il

Examples

A number of complete examples for two- and three-electron systems are given in examples/esr_solids folder. A good way to proceed (soft_3_pulse_deer_2e.m example file) is to look at how the pulses affect the system:

then to inspect the echo stack as a function of the pump pulse position:

and finally to inspect the principal components of the echo stack. The most prominent component is the DEER trace, the other components come from the finite size of the spherical integration grid.

Notes

1. For the method, start with 'expm', change to 'expv' if the calculation runs out of memory, and use 'evolution' as the last resort.
2. Simulated echoes tend to be sharp and hard to catch because simulation does not have distributions in experimental parameters. Fourier transforming the echo prior to integration is recommended.
3. The time in the DEER trace refers to the second pulse insertion point, after end of first pulse.

See also

deer_3p_hard_echo.m, deer_3p_hard_deer.m, deer_analyt.m, eseem.m, oopeseem.m, deer_4p_soft_deer.m, deer_4p_soft_hole.m, deer_4p_soft_diag.m, deer_3p_soft_hole.m, deer_3p_soft_diag.m

Version 2.4, authors: Ilya Kuprov