Accurate 12D dipole moment surfaces of ethylene

- Accurate ab initio full-dimensional dipole moment surfaces of ethylene are computed.
- Excellent agreement with available experimental data is achieved.
- Accuracy permits to resolve issues related to the behavior of intensity patterns.

Accurate ab initio full-dimensional dipole moment surfaces of ethylene are computed using coupled-cluster approach and its explicitly correlated counterpart CCSD(T)-F12 combined respectively with cc-pVQZ and cc-pVTZ-F12 basis sets. Their analytical representations are provided through 4th order normal mode expansions. First-principles prediction of the line intensities using variational method up to J = 30 are in excellent agreement with the experimental data in the range of 0-3200 cm−1. Errors of 0.25-6.75% in integrated intensities for fundamental bands are comparable with experimental uncertainties. Overall calculated C2H4 opacity in 600-3300 cm−1 range agrees with experimental determination better than to 0.5%.

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