# Acquire.m

Forward time evolution with signal acquisition.

## Syntax

    fid=acquire(spin_system,parameters,H,R,K)


## Description

The function propagates the initial condition forward in time and returnes the dynamics of the projection of the densty matrix onto the specified detection state. This function should notmally be called from inside a context function.

## Arguments

    parameters.sweep       -   digitization bandwidth, the equivalent time step is 1/parameters.sweep

parameters.npoints     -   number of time steps to take

parameters.rho0        -   initial state

parameters.coil        -   detection state

parameters.decouple    -   spins to decouple during the evolution, e.g. {'15N','13C'}

H                      -   Hamiltonian commutation superoperator

R                      -   unthermalised relaxation superoperator

K                      -   chemical kinetics superoperator


## Returns

    fid                    -   time dynamics of the detection state


## Examples

The following NMR spectrum is returned by examples/nmr_liquids/pa_rotenone.m function. The corresponding free induction decay is simulated by specifying L+ as the initial condition and then calling acquire().

## Notes

This function may be used to save time in pulse-acquire experiment simultaions by giving it the analytical result of the pulse as the initial condition.