ZPVA contribution

Table 13 Comparison of the electronic and ZPVA contributions to the SHG hyperpolarizability of 4-nitroaniline, from ref 91...

Note that the first two terms on the rhs of Eq. (13), which are first-order, constitute the zpva contribution. All the remaining terms are second-order. The same expressions may be obtained from the double power series expansion. 

The ZPVA contributions for the considered sulfides are very small, but the relativistic contribution has a significant effect on this small quantity. The pure vibrational contribution is small, but not negligible. The relativistic correction has a very significant effect on this contribution of HgS. One may compare the CCSD(T) values for the pure vibrational contribution to Pzzz of HgS, which are —176.6 a.u. (nonrelativistic) and —44.8 a.u. (relativistic). The following sequence is observed (CCSD(T) values with vibrational and relativistic corrections) ... 

Table 5.27 ZPVA and c-ZPVA contributions to the diagonal components of electric properties in the direction of ft for NH3 the fuU-valence Cl values were obtained using fourth-order and...

Pzzz- The vibrational contribution is quite large. Specifically the pure vibrational correction is 35% of the total property. The ZPVA correction is about an order of magnitude smaller than the pure vibrational contribution. There is a perfect agreement between the CASSCF/NC and the CASSCF/BKPT results. Correlation (CASPT2) has a very significant effect on all contributions (Table 5.3) [20]. 

The NR electronic contribution increases with the atomic number of the metal. At the relativistic level, a maximum value is observed for AgH (Tables 5.5 and 5.6). The relativistic correction has a significant effect on the ZPVA and pure vibrational contributions of AgH, and in particular of AuH. The relaxation and curvature contributions are small (Table 5.5). 

ZPVA and pure vibrational (PV) contribution calculated according with to Bishop-Kirtman PT... 

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