A systematic study of basis set, electron correlation, and geometry effects on the electric multipole moments, polarizability, and hyperpolarizability of HCl

The electric multipole moments, dipole and quadrupole polarizability and hyperpolarizability of hydrogen chloride have been determined from an extensive and systematic study based on finite-field fourth-order many-body perturbation theory and coupled-cluster calculations. Ou best values for the dipole, quadrupole, octopole and hexadecapole moment at the experimental internuclear separation of R-e = 2.408 645a(0) are mu = 0.423Xea(0), Theta = 2.67ea(0)(2), Omega = 3.94ea(0)(3), and Phi = 13.37ea(0)(4), respectively. For the mean and the anisotropy of the dipole polarizability alpha(alpha beta) we recommend <(alpha)over bar> = 17.41+/-0.02 and Delta alpha = 1.60+/-0.03e(2)a(0)(3)E(h)(-1). For the mean value of the first dipole hyperpolarizability beta(alpha beta gamma) we advance <(beta)over bar>=-6.8+/-0.3e(3)a(0)(3)E(h)(-7). Extensive calculations with a [8s6p6d3f/5s4p2d1f] basis set at the CCSD(T) level of theory yield the R-dependence of the Cartesian components and the mean of the second dipole hyperpolarizability gamma(alpha beta gamma delta) (R)/e(4)a(0)(4)E(h)(-3) around R-e as y(zzzz)(R) = 1907 + 1326(R-R-e) + 570(R-R-e)(2) + 10(R-R-e)(3)-40(R-R-e)(4), gamma(xxxx)(R) = 3900 + 747(R-R-e)-65(R-R-e)(2)-38(R-R-e)(3)-7(R-R-e)(4), gamma(xxzz)(R) = 962 + 222(R- 21(R-R-e)(3)-9(R-R-e)(4), with z as the molecular axis. The present investigation suggests an estimate of (26.7+/-0.3) x 10(2)e(4)a(0)(4)E(h)(-3) for the Hartree-Fock limit of the mean value <(gamma)over bar> at R-e. CCSD(T) calculations with basis sets of [8s6p6d3f/5s4p2d1f] and [9s7p5d4f/6s5p4d1f] size and MP4 calculations with the even larger [15s12p7d3f/12s7p2d1f] give (7.0+/-0.3) x 10(2)e(4)a(0)(4)E(h)(-3) for the electron correlation effects for this property, thus leading to a recommended value of <(gamma)over bar>=(33.7+/-0.6) x 10(2)e(4)a(0)(4)E(h)(-3). For the quadrupole polarizability C-alpha beta,C- gamma delta/e(2)a(0)(4)E(h)(-1) at R-e our best values are C-zz,C-zz=41.68, C-xz,C-xz=26.11, and C-xx,C-xx=35.38, calculated with the [9s7p5d4f/6s5p4d1f] basis set at the CCSD(T) level of theory. The following CCSD(T) values were obtained with [8s6p6d3f/5s4p2d1f] at R-e: dipole-quadrupole polarizability A(alpha,beta gamma)/e(2)a(0)(3)E(h)(-1), A(z,zz)=14.0, and A(x,xx)=3.75, dipole-octopole polarizability E-alpha,E-beta gamma delta/e(2)a(0)(4)E(h)(-1), E-z,E-zzz=20.0, and E-x,E-xxx=3.0, and dipole-dipole-quadrupole hyperpolarizability B-alpha beta,B-gamma delta/e(3)a(0)(4)E(h)(-2). B-zz,B-zz=-277, B-xz,B-xz=-261, B-xx,B-zz=246, and B-xx,B-xx=-416. A comparison of the mean B polarizability and hyperpolarizability of some 18-electron systems shows that <(alpha)over bar>(H2S) > <(alpha)over bar>(HCl) > <(alpha)over bar>(HOOH) > <(alpha)over bar>(HOF) > <(alpha)over bar(Ar) > <(alpha)over bar(F-2), and <(gamma)over bar>(H2S) > <(gamma)over bar>(HCl) > <(gamma)over bar>HOOH) > <(gamma)over bar>(HOF) approximate to <(gamma)over bar>(Ar) > <(gamma)over bar>(F-2). (C) 1998 American Institute of Physics. [S0021-9606(98)00312-2].