Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction. Issue 16 (2nd May 2018)

• Record Type: Journal Article
• Authors: Shan, Shimin; Yin, Shuang; Lian, Yi; Xu, Haifeng; Yan, Bing
• Is Part Of: International journal of quantum chemistry. Volume 118:Issue 16(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-05-02
• Subjects: core‐valence correlation -- icMRCI+Q -- nitrenes -- scalar relativistic effect -- spectroscopic constants -- spin‐orbit coupling effect; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.25649
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: Internally contracted multireference configuration interaction (icMRCI) calculations of the ground state (X 3 Σ − ), the first excited state (a 1 Δ) as well as the second excited state (b 1 Σ + ) have been performed for a series of halogenated nitrenes NXs (X = Cl, Br, and I). Accurate spectroscopic constants of these lowest three electronic states of each NX were obtained in this work using MRCI methods with aug‐cc‐pVXZ (X = T, Q, 5) basis sets and complete basis set (CBS) limit. In addition, various corrections, including the Davidson correction, scalar relativistic effect, core‐valence correlation, and spin‐orbit coupling effect, have been studied in calculating spectroscopic constants, especially for heavy‐atom nitrenes. Comparisons have been made with previous computational and experimental results where available. The icMRCI + Q calculations presented in this work provide a comprehensive series of results at a consistent high level of theory for all of the halogenated nitrenes. Abstract : Halogenated nitrenes NXs (X = F, Cl, Br, I) are sextet, neutral, and highly reactive molecular species where the nitrogen atom displays monovalent nature. This class of molecules plays an important photochemical role in the upper atmosphere and interstellar space. Insights in the singlet‐triplet gap are of critical importance for the understanding the chemistry of nitrenes, due to the remarkably different chemical reactivity of the two states. The singlet‐triplet gap is ligand dependent in NXs.