Previous using three-diagonal matrix

Solve the previous system using the three-diagonal matrix obtained by A as a preconditioner matrix. The program is... 

All of the magnetic and electric hyperfine matrix elements were derived in our discussion of the LiO spectrum. We now use the symbol m to denote nuclear spin-free terms, as listed above in equations (8.406), and denote the hyperfine terms, previously given in equations (8.384) and (8.385), by the symbol hf. Since the 14N nucleus has spin 7=1, each J level is split into three hyperfine levels, characterised by / =./,. / 1, except for the J = 1 /2 level which has only two hyperfine components, with F = 1 /2 and 3 /2. Consequently if we neglect matrix elements off-diagonal in J for the moment, each characteristic set of J, F levels is described by a 4 x 4 matrix, or two 2x2 matrices, as follows. 

In the previous. section we discussed the reference force field of /-PA (see Table 6.2) derived from the force field of butadiene. In the Og symmetry block, the high frequency C—H stretch is decoupled from the other modes and thus from tt electrons. We are left with three relevant Ug modes their reference and experimental frequencies are reported in Table 6.3 and, as discussed in Section II, fix the matrix and the x cd) curves in Fig. 6.4. The A matrix is written on the basis of the reference normal coordinates Q . It consequently depends on both the G and F matrices and varies with molecular or polymeric structure. The e-ph coupling constants g, thus vary even with isotopic substitution. To define coupling constants independent of mass, we use the symmetry coordinates to solve the GF problem for the reference state. In fact, diagonalization of GF gives both eigenvector matrix L in the S basis. The L matrix is used to transform Jin Eq. (12) back to the S basis ... 

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