Gauge-origin independent calculations of electric-field-induced second-harmonic generation circular intensity difference using London atomic orbitals

ABSTRACT

We present the first gauge-origin independent calculations of the circular intensity difference (CID) in electric-field-induced second-harmonic generation (EFISHG), including all contributions up to the electric-quadrupole–magnetic-dipole level. A recursive, open-ended response theory framework in combination with the use of London atomic orbitals allows us to ensure gauge-origin independent results. We apply this approach to study EFISHG-CID in a collection of chiral amino acids. We demonstrate that diffuse polarising basis functions are critical in order to obtain accurate CIDs, and that a basis set of at least aug-cc-pVTZ quality is needed in order to obtain results close to the basis-set limit. The use of London orbitals does not lead to significantly faster basis set convergence, although the improved basis set convergence allows the aug-cc-pVDZ basis set to be used with some confidence for larger molecules.

KEYWORDS:

• Molecular properties
• London atomic orbitals
• electric-field-induced second-harmonic generation
• circular intensity differences

Acknowledgment

It is a great pleasure for us to dedicate this paper to Prof. Hans Jørgen Aa. Jensen on the occasion of his 60th birthday.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has received support from the Research Council of Norway through a Centre of Excellence Grant [grant number 179568]; the Norwegian Supercomputing program through a grant of CPU resources [grant number NN4654K].