Brenda Lam

Vibrational polarizabilities for H2+, H2 and N2

Abstract General formulae for the purely vibrational contributions to the static polarizabilities Aα,βγ, Bα,β,γδ,and Cαβ,γδ are presented. As specific examples, the vibrational contributions to the γ, B, and C tensors for H2+, H2 and N2 are calculated. In addition values of the hexadecapole moment for H2+ at a series of internuclear distances are given.

Field and field-gradient polarizabilities of LiH

Using a charge-perturbation approach, all components of the polarizability tensors α, β, A, B, and C for H2O have been evaluated at the SCF level and, with the exception of β and B, at the MC SCF level of approximation. This is the first such comprehensive evaluation of the electrical properties of water.

Calculation of the dc Kerr and electric‐field‐induced second‐harmonic generation susceptibilities for H2 and D2

A comprehensive theoretical investigation of the third‐order susceptibilities for the nonlinear optical processes dc Kerr and dc electric‐field‐induced second‐harmonic generation is reported for H2 and D2. Accurate wave functions of the J ames–Coolidge‐type, which account for electronic correlation, are utilized and particular attention is given to the effects of vibration. Results for both the parallel and perpendicular components of the susceptibilities are given for λ=∞, 10 640, 6943, 6328, 5900, 5145, and 4880 A. These are sufficient to enable a direct comparison with certain experimental data and, in general, the agreement is within the expected error bounds.

An analysis of the interaction between a distant point charge and H2

With the calculation of the two independent components of the dipoleoctupole polarizability tensor (E) of H2 + we complete our knowledge of all polarizability tensors of this ion up to fourth-rank. These tensors may be directly used to investigate the effect of a distant charge on the isolated nuclear-fixed molecule. On the other hand, if the molecule is rotating then orientationally-averaged values (which include vibrational and rotational contributions) must be used and these are tabulated here for the lowest eleven rotational states for the ground vibrational state of H2 +. Attention is drawn to the fact that these two situations lead to equations which are both qualitatively and quantitatively different.

The Stark effect and polarizabilities for a diatomic molecule

The influence of a uniform static electric field on both a single and a collection of diatomic molecules is analyzed in detail. Comparison is made with less rigorous and more ad hoc treatments and numerical results are given for 7LiH and 19FH which show the limitations of frequently invoked approximations.

Field and field-gradient polarizabilities of BeH, BH and CH+

Abstract The multipole moments and independent components of the α, β, A, C, and B polarizability tensors have been calculated for BeH, BH, and CH+ at both SCF and MC SCF levels. To our knowledge, this is the first time that electron correlation has been taken into account in evaluating these properties for these species.

The dynamic quadrupole and dipole–quadrupole polarizabilities of helium

The dynamic quadrupole and dipole−quadrupole polarizabilities of heliu are calculated, using variation−perturbation theory and electron− correlated wavefunctions.(AIP)

Hyperpolarizabilities of diatomic molecules: The effects of vibration and rotation

Abstract The inductive properties of a non-polar diatomic molecule in a static non-uniform electric field are best described in terms of its dipole polarizability (α), second hyperpolarizability (γ), quadrupole-quadrupole polarizability ( C ) and dipole-di-pole-quadrupole polarizability ( B ). We present formulae for these quantities which take into account both vibration and rotation. We do so in a more general way than hitherto by placing an electric field and field gradient along an arbitrary laboratory axis rather than along a molecular axis. These formulae are then compared with those which can be obtained by accounting for rotation by classical orientational averaging, which involve polarizabilities defined with respect to molecular axes. Results for H 2 + and H 2 show that the “electronic” contributions are similar in both treatments, but the “vibrational” and “rotational” contributions are not. This is particularly so when the molecules are not in the lowest vibrational state.

An ab initio study of third-order non-linear optical properties of H+ 2

Values are reported for the first time for the components and isotropic averages of the second hyperpolarizabilities (γ) for H+ 2 which are relevant to the four non-linear optical processes: d.c. Kerr, discrete four-wave mixing, electric-field-induced second harmonic generation, and third harmonic generation. The effects of change of internuclear separation and change of laser frequency (dispersion) are investigated.