Topological effects in low-lying electronic states of linear N₂H₂⁺ and HBNH⁺ associated with onset of bending

ABSTRACT

The current decade has seen illuminating and extensive study of interplay of topological effects such as Renner–Teller and Jahn–Teller (JT) effects in small molecules. Study of such effects in HCNH molecule showed an interesting feature that for slightly bent system, a pair of JT conical interactions (CIs) appear only for certain nonplanar configuration, in contrast to its appearance in C_S configuration (molecular plane) for C₂H₂ ⁺. Moreover, since the feature of appearance of JT-CIs in two ²Σ⁺ states of HCNH in some bent configuration may be critically associated to the abundance of HNC in interstellar spaces, as advocated recently by Das and Mukhopadhyay (J. Phys. Chem. 117, 8680 (2013)), the interest in such topological studies have remained relevant. In this article we have investigated such topological effects for slightly bent N₂H₂ ⁺ and HBNH⁺. Interestingly, the appearance of JT-CIs are, for HBNH⁺, in molecular plane while for N₂H₂ ⁺, in certain nonplanar configuration, in sharp contrast to the effect in the otherwise similar pair of molecular systems, C₂H₂ ⁺ and HCNH.

GRAPHICAL ABSTRACT

KEYWORDS:

• Molecular electronic states
• electronic non-adiabatic effects
• Renner–Teller
• Jahn–Teller

Acknowledgment

RM acknowledges UGC, India for a fellowship and AD acknowledges SERB, India, for providing National Post Doctoral Fellowship (N-PDF application no. PDF/2017/ 000315). DM acknowledges BRNS(DAE, India) Project (No. 2009/37/42/BRNS) for computational facility.

Disclosure statement

No potential conflict of interest was reported by the authors.