Efficient Ab Initio Calculation of Polyatomic Ro-vibrational Spectra: A Comparative Study of Discrete Variable Representations for NH <sub>2</sub> with Non-Adiabatic Coupling
We theoretically investigated the rotational-vibrational (ro-vibrational) spectrum of the NH<sub>2</sub> molecule in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mover><mml:mi>X</mml:mi><mml:mo>~</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>A</mml:mi><mml:mo>″</mml:mo></mml:msup></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mover><mml:mi>A</mml:mi><mml:mo>~</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>A</mml:mi><mml:mo>'</mml:mo></mml:msup></mml:math> electronic states. Because the ground electronic state <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mover><mml:mi>X</mml:mi><mml:mo>~</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>A</mml:mi><mml:mo>″</mml:mo></mml:msup></mml:math> and the first excited state <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mover><mml:mi>A</mml:mi><mml:mo>~</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>A</mml:mi><mml:mo>'</mml:mo></mml:msup></mml:math> have nonlinear equilibrium geometries, the Renner-Teller (RT) effect plays a significant role in the ro-vibrational spectrum. By introducing the RT effect as an effective coupling potential of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mover><mml:mi>X</mml:mi><mml:mo>~</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>A</mml:mi><mml:mo>″</mml:mo></mml:msup></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mover><mml:mi>A</mml:mi><mml:mo>~</mml:mo></mml:mover><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>A</mml:mi><mml:mo>'</mml:mo></mml:msup></mml:math> states, the ro-vibrational spectra at different total angular momentum quantum numbers are calculated with the generalized Laguerre discrete variable representation (LDVR), Laguerre-Morse DVR (LMDVR), and Jacobi DVR (JDVR). Additionally, we conduct a comparative analysis of the efficiency of Laguerre, Laguerre-Morse, Jacobi, and conventional sine DVR in calculating the ro-vibrational spectra. The results of the ab initio calculations are presented in this work as well as the data and code for the potential energy surface (PES) part of the Hamiltonian with the RT effect.
Authors
- Zhongchen Xing (ORCID: https://orcid.org/0000-0003-4173-4038)
- Chen Zhang (ORCID: https://orcid.org/0000-0002-2544-4746)
- Shulan Zhou
- Chengyin Wu (ORCID: https://orcid.org/0009-0006-4643-9360)
- Gaoxing Song
- Zheng Li
- Boya Qin
- Ming Zhang
Institutions
- Shandong University of Technology (CN)
- Shanghai Jiao Tong University (CN)
- Peking University (CN)
- University of Oxford (GB)
- Collaborative Innovation Center of Quantum Matter (CN)
- Wuhan National Laboratory for Optoelectronics (CN)
- Shanxi University of Traditional Chinese Medicine (CN)
- Heinz Optical Engineering (United States) (US)
- Huazhong University of Science and Technology (CN)
- Wuhan Institute of Technology (CN)
Publication Details
- Journal
- The Journal of Physical Chemistry A
- Published
- 2026-02-18
- DOI
- https://doi.org/10.1021/acs.jpca.5c06688
- Primary Topic
- Advanced Chemical Physics Studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00