ELECTRIC PROPERTIES OF IONIC DIATOMS - BEO

A series of extensive calculations has been carried out in order to establish reliable data for the basic electric properties of the X 1-SIGMA-+ electronic ground state of BeO. The most reliable calculations have been carried out by using coupled cluster methods and have resulted in the following data: dipole moment, mu = -2.308 au, quadrupole moment, theta = 4.39 au, dipole polarizability, alpha-xx = alpha-perpendicular-to = 35.98 au, alpha-zz = alpha-parallel-to = 44.29 au, quadrupole polarizability, C(xx,xx) = 51.6 au, C(zz,zz) = 78.0 au, C(xz,xz) = 81.1 au. The reliability of the calculated electric properties has been assessed by comparing the results of different methods. The data are discussed in terms of the electronic structure of the X 1-SIGMA-+ state of BeO. The most reliable calculation of the electric field gradient of BeO gives the value of 0.0297 au which can be used for the accurate determination of the Be-9 nuclear quadrupole moment from molecular microwave data.