solid state nmr section 4 part 2

what is the quadrupolar interaction?

occurs when the spin of the nucleus is 1 and is the dominant anisotropic interaction in solid state 2H nmr

it is the interaction between the electric quadrupole moment of the nucleus and the electric field gradient at the site of the nucleus

it is averaged to 0 in liquid state, depends on orientation of the crystal relative to Bo in solid state

what is the splitting between 2 lines in a 2H nmr spectrum of a molecule with axial symmetry?

¾ (3cos²(theta) - 1) chi

theta = angle between Bo and crystal

chi = quadrupole coupling constant, depends on the local structure around the 2H nucleus

how can you study molecular motions using solid state 2H NMR?

record experimental spectra as a function of temperature

simulate the data computationally for different mechanisms and rates

compare the two to see which mechanism it matches best and which rate

especially sensitive to X - 2H bond reorientation and in the range 10³ - 10^7 s^-1 for line shape analysis and 10^4 - 10^11 for T1 measurements

what is an example of a molecular motions using you may want to study?

guest molecules in a host relationship