Analytical potential energy surfaces for N(3) low-lying doublet states
Zhi Wang1, Ioannis S K Kerkines, Keiji Morokuma
1Department of Chemistry and Cherry Logan Emerson Center for Scientific Computation, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
The Journal of Chemical Physics
|February 5, 2009
Summary
This study constructs potential energy surfaces for nitrogen tri-atom (N3) states using advanced computational methods. The findings provide accurate models for N3 dynamics and reactivity, crucial for understanding chemical reactions.
Area of Science:
- Computational Chemistry
- Theoretical Chemistry
- Quantum Chemistry
Background:
- Nitrogen tri-atom (N3) is a key species in atmospheric and combustion chemistry.
- Accurate potential energy surfaces (PESs) are essential for understanding N3 dynamics and reactivity.
- Previous studies have limitations in describing the complex electronic states of N3.
Purpose of the Study:
- To construct accurate adiabatic and diabatic potential energy surfaces (PESs) for low-lying doublet states of N3.
- To develop a novel fitting strategy combining global and local approaches for improved PES accuracy.
- To investigate conical intersection regions and diabatic couplings in the N3 system.
Main Methods:
- 1504 single-point calculations using MRCISD(Q) level with aug-cc-pVTZ basis set.
- A hybrid fitting strategy: global fits for individual PESs and local simultaneous fits for coupled states.
- Inclusion of switching functions and permutational symmetry in basis functions for accurate fitting.
- Identification and analysis of stationary points and conical intersections.
Main Results:
- Accurate adiabatic PESs for five low-lying doublet states of N3 were constructed with root-mean-square errors of 2-3 kcal/mol.
- A novel fitting strategy effectively captured the complex behavior near conical intersections.
- Stationary points and seam minima were located and showed good agreement with ab initio data.
- Diabatic PESs and coupling potential for the 1(2A') and 2(2A') states were successfully generated.
Conclusions:
- The developed PESs provide a reliable theoretical foundation for future dynamical studies of N3.
- The hybrid fitting strategy represents an advancement in constructing accurate PESs for polyatomic systems.
- The study offers valuable data for understanding the electronic structure and reactivity of N3.
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