For 10 points, name this type of spectroscopy in which an external magnetic field is applied to a sample.
One form of this technique uses the equation three cosine square of theta minus one; that equation vanishes at the magic angle of 54.7 and is the solid state form. Another form of this technique is distortionless enhancement of polarization transfer. The nuclear Overhauser effect forms the basis of a two-dimensional form of it. In this technique, n plus one multiplets whose ratios follow Pascal's triangle can be created by J-coupling. The relationship between the dihedral angle of vicinal hydrogens and its namesake coupling constant is described by the Karplus equation. Spin-lattice and spin-spin are two types of relaxation that can occur in this technique. It uses TMS as a reference to measure the relative chemical shifts of a sample, and common varieties of it include proton and carbon-13. For 10 points, name this type of spectroscopy in which an external magnetic field is applied to a sample.
One form of this technique uses the equation three cosine square of theta minus one; that equation vanishes at the magic angle of 54.7 and is the solid state form.
NMR spectroscopy [or nuclear magnetic resonance spectroscopy]