SEARCH Articles Figures Tables Density matrix approach to nuclear spin relaxation Density relaxation Density relaxation Electron density spin relaxation High-density polyethylene relaxation Perturbation theory relaxed density matrix Polyethylene, high-density relaxation transitions Reduced density matrix vibrational relaxation Relaxation crosslink density Relaxation mechanisms density matrix method Relaxation network density Relaxation of Charge Density Relaxation processes density matrix Silicate density relaxation Spectral density, hydrogen bonds relaxation