XVi LIST OF SYMBOLS I(k,t) intermediate scattering function (2.7) molecule index (1.3.2) j particle current (8.2) j energy current 2.7) J total angular momentum (3.6.1) k generalized coordinate or molecule index (1.3.2) k Boltzmann's constant (1.2) k wave vector (1.5.2) kinetic energy (1.3.1) cell length (5.3.2) L box length (1.5.2) L Liouville operator (always found as iL) (2.1) L angular momentum (3.1) 9 Lagrangian (3.1) m molccular mass (1.3.1) m possible outcome or state label (4.3) M memory function matrix (9.2) n possible outcome or state label (4.3) N number of molecules (1.3.1) 0 octopole moment (1.3.3) P molecular momentum (1.3.1) P pressure (2.4) P Legendre polynomial (2.6) P total linear momentum (2.2) e instantaneous pressure (2.4) P instantaneous pressure tensor (2.7) P projection operator (9.2) generalized coordinates (1.3.1) e quadrupole moment (1.3.3) o partition function (2.1) Q quaternion (3.3.1) Q projection operator (9.2) molecular separation (1.3.2) molecular position (1.3.1) r订 position of molecule i relative to j(ri) (1.3.2) Ia site-site vector (short for ria-jb) (2.4 凳 region of space (4.4) statistical inefficiency (6.4.1) scaled time variable (7.4.2) 3 scaled molecular position (4.5) S entropy (2.2) S(k) structure factor (2.6 Sk,ω) dynamic structure factor (2.7 S total intrinsic angular momentum (spin) (3.6.1) 9 action integral (10.2) t time (2.1) t correlation or relaxation time (2.7) T temperature (1.2)