Configuration Interaction Calculations Research Articles

Probing the quadrupole transition strength of C15 via deuteron inelastic scattering

Deuteron elastic scattering from $^{15}\mathrm{C}$ and inelastic scattering reactions to the first excited state of $^{15}\mathrm{C}$ were studied using a radioactive beam of $^{15}\mathrm{C}$ in inverse kinematics. The scattered deuterons were measured using HELIOS. The elastic scattering differential cross sections were analyzed using the optical model. A matter deformation length ${\ensuremath{\delta}}_{d}=1.04(11)\phantom{\rule{0.16em}{0ex}}\mathrm{fm}$ has been extracted from the differential cross sections of inelastic scattering to the first excited state. The ratio of neutron and proton matrix elements ${M}_{n}/{M}_{p}=3.6(4)$ has been determined from this quadrupole transition. Neutron effective charges and core-polarization parameters of $^{15}\mathrm{C}$ were determined and discussed. Results from ab initio no-core configuration interaction calculations were also compared with the experimental observations. This result supports a moderate core decoupling effect of the valence neutron in $^{15}\mathrm{C}$ similarly to its isotone $^{17}\mathrm{O}$, in line with the interpretation of other neutron-rich carbon isotopes.

Destruction of phosphorus nitride through the N(4S) + PN(1Σ+) → N2(1Σ+) + P(4S) reaction

ABSTRACT The study of reactions involving phosphorus bearing species (PBS) in star-forming regions as well as in circumstellar envelopes are important to elucidate the mechanisms in which this element is formed and destroyed, and perhaps, lead to important pre-biotic molecules. Phosphorus nitride (PN) is the most easily detected PBS in the interstellar medium (ISM), and is considered as one of the major reservoirs of this element in the ISM. However, only a few of its reactions have been analysed experimentally or computationally. Therefore, modelling PN chemistry and interpretation of the observations suffer uncertainties, affecting our astrochemical understanding of this species. In this work, we perform explicitly correlated multireference configuration interaction (MRCI+Q/AVTZ+d//CAS/AVTZ+d) calculations on the destruction of PN through the N(4S) + PN(1Σ+) reaction. We have also performed DFT (M06-2X) and CCSD(T) calculations for benchmark purposes. Rate coefficients over a large range of temperatures were computed using standard transition state theory (TST), canonical variational TST (CVT), and also incorporating tunneling effects with the small curvature tunneling method (SCT). We found that the NPN system possesses a considerable multireference character, and the DFT approach cannot properly describe the available destruction mechanisms. Our best estimate for the rate coefficients, at the MRCI+Q/AVTZ+d level, can be described by the modified Arrhenius equation 1.09×10−11(T/300)−1.02exp (− 7919/T). We show for the first time that this reaction may be considerably fast in shock regions and in high temperature environments of solar-type star forming regions, and of significant importance to model the abundance of PN in such environments.

A recursive formulation of one‐electron coupling coefficients for spin‐adapted configuration interaction calculations featuring many unpaired electrons

AbstractThis work reports on a novel computational approach to the efficient evaluation of one‐electron coupling coefficients as they are required during spin‐adapted electronic structure calculations of the configuration interaction type. The presented approach relies on the equivalence of the representation matrix of excitation operators in the basis of configuration state functions and the representation matrix of permutation operators in the basis of genealogical spin eigenfunctions. After the details of this connection are established for every class of one‐electron excitation operator, a recursive scheme to evaluate permutation operator representations originally introduced by Yamanouchi and Kotani is recapitulated. On the basis of this scheme we have developed an efficient algorithm that allows the evaluation of all nonredundant coupling coefficients for systems with 20 unpaired electrons and a total spin of within only a few hours on a simple Desktop‐PC. Furthermore, a full‐CI implementation that utilizes the presented approach to one‐electron coupling coefficients is shown to perform well in terms of computational timings for CASCI calculations with comparably large active spaces. More importantly, however, this work paves the way to spin‐adapted and configuration driven selected configuration interaction calculations with many unpaired electrons.

Quantum-Compute Algorithm for Exact Laser-Driven Electron Dynamics in Molecules.

In this work, we investigate the capability of known quantum computing algorithms for fault-tolerant quantum computing to simulate the laser-driven electron dynamics of excitation and ionization processes in small molecules such as lithium hydride, which can be benchmarked against the most accurate time-dependent full configuration interaction (TD-FCI) calculations. The conventional TD-FCI wave packet propagation is reproduced using the Jordan-Wigner transformation for wave function and operators and the Trotter product formula for expressing the propagator. In addition, the time-dependent dipole moment, as an example of a time-dependent expectation value, is calculated using the Hadamard test. To include non-Hermitian operators in the ionization dynamics, a similar approach to the quantum imaginary time evolution (QITE) algorithm is employed to translate the propagator, including a complex absorption potential, into quantum gates. The computations are executed on a quantum computer simulator. By construction, all quantum computer algorithms, except for the QITE algorithm used only for ionization but not for excitation dynamics, would scale polynomially on a quantum computer with fully entangled qubits. In contrast, TD-FCI scales exponentially. Hence, quantum computation holds promises for substantial progress in the understanding of electron dynamics of excitation processes in increasingly large molecular systems, as has already been witnessed in electronic structure theory.

Extended Calculations of Atomic Structure Parameters for Na-like Ar, Kr and Xe Ions Using Relativistic MCDHF and MBPT Methods

In this study, comprehensive calculations of energies, hyperfine structure constants, Landé gJ factors and isotope shifts have been performed for the lowest 71 states of Na-like Ar7+, Kr25+ and Xe43+ ions. Radiative parameters viz., wavelengths, transition rates, oscillator strengths and lifetimes are estimated for the electric dipole E1 transitions among these levels. The states under consideration include 1s22s22p6nl for n = 3–9, l = 0–6, and the fully relativistic multiconfiguration Dirac–Hartree–Fock (MCDHF) method integrated in the latest version of the general-purpose relativistic atomic structure package (GRASP2018) is used for the calculations. The additional corrections, such as the Breit interaction and quantum electrodynamics effects are included in the relativistic configuration interaction calculations, and their effects on energies and other parameters are analysed. We examined the impact of including the core–core and core–valence correlations on level energies. Furthermore, to inspect the reliability of our MCDHF results, we performed another set of calculations using the many-body perturbation theory built into the Flexible Atomic Code (FAC). Moreover, we estimated the uncertainties in the computed lifetimes and transition parameters and assigned their accuracy class. A thorough comparison between the two obtained calculations and with the previous theoretical and experimental results, wherever available, is carried out and a good agreement is observed.

Comprehensive Study of HCN: Potential Energy Surfaces, State-to-State Kinetics, and Master Equation Analysis.

Understanding the kinetics of the HCN system is critical to several disciplines in science and engineering, including interstellar chemistry, atmospheric reentry, and combustion, to name a few. This paper constructs a rovibrational state-specific kinetic mechanism for the HCN system, leveraging electronic structure calculations, classical scattering dynamics, and state-to-state kinetics. To this aim, three accurate potential energy surfaces (PESs), 1A', 3A', and 3A″, are constructed using multireference configuration interaction (MRCI) calculations for a comprehensive arrangement of the nuclei. Quasi-classical scattering calculations provide elementary reaction rate constants resulting from the interaction between the CN, CH, and NH molecules with H, N, and C atoms, respectively. The rovibrational collisional model developed comprises 50 million bound-bound and free-bound collisional processes. This model is used to study the dynamics of energy transfer and dissociation in an isochoric and isothermal chemical reactor via the solution of the master equation for a wide temperature range from 1000 to 10,000 K. This study unravels the dynamics of dissociation of the molecules in the HCN system, which the PESs primarily control via the formation of short-lived intermediates that shortcut the dissociation pathway. The exchange processes in CH and NH enhance the dissociation by over 80%. The importance of exchange processes is also highlighted in comparing the quasi-steady state and thermal dissociation rates with state-of-the-art rate models and experimental fits.

Tune-out wavelengths for the 2 3S1 state of the Li+ ion

Configuration interaction calculations are performed to determine the dipole polarizabilities and tune-out wavelengths for the $2{\phantom{\rule{0.28em}{0ex}}}^{3}{S}_{1}$ state in ${\mathrm{Li}}^{+}$ ion. The finite nuclear mass correction is given by including the mass shift operator in the Dirac-Coulomb-Breit Hamiltonian directly, while the QED correction to dynamic dipole polarizabilities is evaluated by using the perturbation theory. The tune-out wavelengths for the $2{\phantom{\rule{0.28em}{0ex}}}^{3}{S}_{1}\phantom{\rule{0.28em}{0ex}}({M}_{J}=0)$ and $2{\phantom{\rule{0.28em}{0ex}}}^{3}{S}_{1}\phantom{\rule{0.28em}{0ex}}({M}_{J}=\ifmmode\pm\else\textpm\fi{}1)$ states are 159.620 55(6) nm and 159.631 14(6) nm, respectively. And the QED correction for 159 nm tune-out wavelength is 43 ppm. In addition, we obtain the static dipole polarizability for the $2{\phantom{\rule{0.28em}{0ex}}}^{3}{S}_{1}\phantom{\rule{0.28em}{0ex}}({M}_{J}=\ifmmode\pm\else\textpm\fi{}1)$ state to be 46.857 03(4) a.u., in which the contribution from QED is 70 ppm. The 159 nm tune-out wavelength and the static dipole polarizability of $2{\phantom{\rule{0.28em}{0ex}}}^{3}{S}_{1}$ state might provide a test of atomic structure theory.

Determination of spectroscopic constants from rovibrational configuration interaction calculations

Rotational constants and centrifugal distortion constants of a molecule are the essence of its rotational or rovibrational spectrum (e.g., from microwave, millimeter wave, and infrared experiments). These parameters condense the spectroscopic characteristics of a molecule and, thus, are a valuable resource in terms of presenting and communicating spectroscopic observations. While spectroscopic parameters are obtained from experimental spectra by fitting an effective rovibrational Hamiltonian to transition frequencies, the ab initio calculation of these parameters is usually done within vibrational perturbation theory. In the present work, we investigate an approach related to the experimental fitting procedure, but relying solely on ab initio data obtained from variational calculations, i.e., we perform a nonlinear least squares fit of Watson's A- and S-reduced rotation-vibration Hamiltonian to rovibrational state energies (resp. transition frequencies) from rotational-vibrational configuration interaction calculations. We include up to sextic centrifugal distortion constants. By relying on an educated guess of spectroscopic parameters from vibrational configuration interaction and vibrational perturbation theory, the fitting procedure is very efficient. We observe excellent agreement with experimentally derived parameters.

The excited states of azulene: A study of the vibrational energy levels for the lower ππ*-valence states by configuration interaction and density functional calculations, and theoretical studies of the Rydberg states.

A new vacuum ultraviolet absorption (VUV) spectrum of azulene vapor has been obtained by using a synchrotron radiation source. The onset of the ultraviolet spectrum, previously reported by Sidman et al., has been analyzed in detail by Franck-Condon (FC) and Herzberg-Teller (HT) methods. The photoelectron spectral profile identifies the 3px-Rydberg state 00 band to be 131cm-1 from the VUV maximum. Excited state energy levels were calculated by three independent methods: the wide scan VUV spectrum was correlated with symmetry adapted cluster configuration interaction calculations. The low energy portion of the spectrum was studied by both time dependent density functional theoretical methods (TDDFT) and multi-reference multi-root CI (MRD-CI). Equilibrium structures were determined for valence states at the TDDFT level. Rydberg states were determined by both TDDFT and MRD-CI. The FC + HT analyses were performed on the TDDFT wave-functions. The HT intensity profiles are generally low in intensity, relative to the FC ones; however, HT is dominant in the second singlet state (S2, 11A1). As a result, numerous non-symmetric modes, their overtones, and combination bands show considerable intensity in that band. Energies obtained from use of extremely diffuse s-, p-, d-, or f-character functions enabled realistic extrapolation to the IE1 for many Rydberg states (RS). The lowest RS (3b13s) based on IE2 lies at 4.804eV with a quantum defect of 0.714. Differentiation between valence and RS is readily made using the second moments of the charge distribution.

Precision half-life determination for the β+ emitter N13

A new precision half-life measurement of $^{13}\mathrm{N}$ has been conducted using the TwinSol $\ensuremath{\beta}$-counting station at the University of Notre Dame. The measured value of ${t}_{1/2}^{\mathrm{new}}=597.05(19)\phantom{\rule{4pt}{0ex}}\mathrm{s}$ differs from the previous world value by about $2.8\ensuremath{\sigma}$. An evaluation of the $^{13}\mathrm{N}$ half-life results in a ${t}_{1/2}^{\mathrm{world}}=597.19(22)\phantom{\rule{4pt}{0ex}}\mathrm{s}$. Updated standard model predictions for the Fermi to Gamow-Teller mixing ratio $\ensuremath{\rho}$ and its associated correlation parameters have been calculated using the new $^{13}\mathrm{N}$ world half-life in preparation for a future measurement of the mixing ratio. Finally, an ab initio no-core configuration interaction (NCCI) calculation for the $B(\mathrm{GT})$ of this decay, carried out using the Daejeon16 interaction, has been performed, revealing the need for higher-order chiral corrections.

Extended relativistic multiconfiguration calculations of energy levels and transition properties in singly ionized tin

Multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) calculations are performed for 22 states in singly ionized tin (Sn II) belonging to the 5s2ns(n=6,7), 5s2nd(n=5,6), 5s5p2 even parity configurations and the 5s2np(n=5,6,7), 5s24f odd parity configurations. Valence-valence and core-valence correlation effects are taken into account through configuration state function (CSF) expansions. Complete and consistent data sets of level energies, wavelengths, oscillator strengths, lifetimes and transition rates among all these states are given. The results are compared with existing theoretical and experimental results. There is an excellent agreement for calculated excitation energies with experimental data from the NIST database. Lifetimes and transition rates are also in agreement with the results from previous calculations and available measurements for most of the transitions.

Semiclassical and VSCF/VCI Calculations of the Vibrational Energies of trans- and gauche-Ethanol Using a CCSD(T) Potential Energy Surface.

A recent full-dimensional Δ-Machine learning potential energy surface (PES) for ethanol is employed in semiclassical and vibrational self-consistent field (VSCF) and virtual-state configuration interaction (VCI) calculations, using MULTIMODE, to determine the anharmonic vibrational frequencies of vibration for both the trans and gauche conformers of ethanol. Both semiclassical and VSCF/VCI energies agree well with the experimental data. We find significant mixing between the VSCF basis states due to Fermi resonances between bending and stretching modes. The same effects are also accurately described by the full-dimensional semiclassical calculations. These are the first high-level anharmonic calculations using a PES, in particular a "gold-standard" CCSD(T) one.

Nucleon-pair truncation of the shell model for medium-heavy nuclei

Background: Establishing computationally tractable models of atomic nuclei is a long-time goal of nuclear structure physics. A flexible framework which easily includes excited states and many-body correlations is the configuration-interaction shell model (SM), but the exponential growth of the basis means one needs an efficient truncation scheme, ideally one that includes both deformation and pairing correlations.Purpose: We propose an efficient truncation scheme of the SM: starting from a pair condensate variationally defined by Hartree-Fock single-particle states and the particle-number conserved Bardeen-Cooper-Schrieffer (NBCS) approximation, we carry out projection of states with good angular momentum.Methods: After generating Hartree-Fock single-particle states with Kramers degeneracy in a SM space, we optimize the pair amplitudes in the NBCS by minimizing the energy, and then use linear algebra projection (LAP) of states with good angular momentum. Both NBCS and LAP are computationally fast.Results: Our calculations yield good agreement with full configuration-interaction SM calculations for low-lying states of transitional and rotational nuclei with axially symmetric and triaxial deformation in medium- and heavy-mass regions: $^{44,46,48}\mathrm{Ti}$, $^{48,50}\mathrm{Cr}$, $^{52}\mathrm{Fe}$, $^{60,62,64}\mathrm{Zn}$, $^{66,68}\mathrm{Ge}$, $^{68}\mathrm{Se}$, and $^{108,110}\mathrm{Xe}$. We predict low-lying states of $^{112--114}\mathrm{Ba}$ and $^{116--120}\mathrm{Ce}$, nuclei difficult to reach by large-scale SM calculations.Conclusions: Both pair correlation and the configuration mixing between different intrinsic states play a key role in reproducing collectivity and shape coexistence, demonstrating the utility of this truncation scheme of the SM to study transitional and deformed nuclei.

Reducing the computational load – atomic multiconfiguration calculations based on configuration state function generators

In configuration interaction (CI) calculations the atomic wave functions are given as expansions over configuration state functions (CSFs) built on relativistic one-electron orbitals. The expansion coefficients of the configuration state functions are obtained by constructing and diagonalizing the Hamiltonian matrix. Here we show how a regrouping of the configuration state functions and the introduction of configuration state function generators (CSFGs) allow for a substantial reduction of the computational load in relativistic CI calculations. The computational methodology based on configuration state function generators, recently implemented in the General Relativistic Atomic Structure package (Grasp2018, Froese Fischer et al. (2019) [16]), is applied to a number of atomic systems and correlation models with increasing sets of one-electron orbitals. We demonstrate a reduction of the CPU time with factors between 10 and 14 for the largest CI calculations. The inclusion of the Breit interaction into the calculations is time consuming. By applying restrictions on the Breit integrals we show that it is possible to further reduce the CPU times with factors between 2 and 3, with negligible changes to the computed excitation energies. We also demonstrate that the introduction of configuration state function generators allows for efficient a priori condensation techniques, with reductions of the expansions sizes with factors between 1.5 and 2.5 and the CPU time with factors between 2.5 and 4.5, again with negligible changes to the excitation energies. In total we demonstrate reductions of the CPU time with factors up to 68 for CI calculations based on configuration state function generators, restrictions on the Breit integrals and with a priori condensed expansions compared to ordinary CI calculations without restrictions on the Breit integrals and with full expansions. Further perspectives of the new methodology based on configuration state function generators are given.

Ab initio calculations of the hyperfine structure of 109Cd, 109Cd+ and reevaluation of the nuclear quadrupole moment Q(109Cd)

Large scale ab initio calculations of the electric contribution (i.e. the electric field gradient (EFG)) to the electric quadrupole hyperfine interaction constants B for the state of 109Cd+ ion and the states of neutral 109Cd atom were performed. To probe the sensitivity of B to different electron correlation effects, six sets of variational multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction calculations employing different strategies were carried out. The calculated EFGs, together with experimental values of B, allow us to extract a new value of the nuclear electric quadrupole moment Q(109Cd) = 0.634(22) b which is about 5% larger than the recommended value (Stone 2016 At. Data Nucl. Data Tables 111–112 1; Pyykkö 2018 Mol. Phys. 116 1328). Efforts were made to provide a realistic theoretical uncertainty for the final Q value based on statistical principles and correlation with the magnetic dipole hyperfine interaction constant A.

Ab initio estimation of E2 strengths in Li8 and its neighbors by normalization to the measured quadrupole moment

For electric quadrupole ($E2$) observables, which depend on the large-distance tails of the nuclear wave function, ab initio no-core configuration interaction (NCCI) calculations converge slowly, making meaningful predictions challenging to obtain. Nonetheless, the calculated values for different $E2$ matrix elements, particularly those involving levels with closely-related structure (e.g., within the same rotational band) are found to be robustly proportional. This observation suggests that a known value for one observable may be used to determine the overall scale of $E2$ strengths, and thereby provide predictions for others. In particular, we demonstrate that meaningful predictions for $E2$ transitions may be obtained by calibration to the ground-state quadrupole moment. We test this approach for well-measured low-lying $E2$ transitions in $^7$Li and $^9$Be, then provide predictions for transitions in $^8$Li and $^9$Li. In particular, we address the $2^+\rightarrow1^+$ transition in $^8$Li, for which the reported measured strength exceeds ab initio Green's function Monte Carlo (GFMC) predictions by over an order of magnitude.

Correction of residual errors in configuration interaction electronic structure calculations.

Methods for correcting residual energy errors of configuration interaction (CI) calculations of molecules and other electronic systems are discussed based on the assumption that the energy defect can be mapped onto atomic regions. The methods do not consider the detailed nature of excitations but instead define a defect energy per electron that is unique to a specific atom. Defect energy contributions are determined from calculations on diatomic and hydride molecules and then applied to other systems. Calculated energies are compared with experimental thermodynamic and spectroscopic data for a set of 41 mainly organic molecules representing a wide range of bonding environments. The most stringent test is based on a severely truncated virtual space in which higher spherical harmonic basis functions are removed. The errors of the initial CI calculations are large, but in each case, including defect corrections brings calculated CI energies into agreement with experimental values. The method is also applied to a NIST compilation of coupled cluster calculations that employ a larger basis set and no truncation of the virtual space. The corrections show excellent consistency with total energies in very good agreement with experimental values. An extension of the method is applied to dmsn states of Sc, Ti, V, Mn, Cr, Fe, Co, Ni, and Cu, significantly improving the agreement of calculated transition energies with spectroscopic values.

The AuSc, AuTi, and AuFe molecules: Determination of the bond energies by Knudsen effusion mass spectrometry experiments combined with ab initio calculations.

The AuTi gaseous molecule was for the first time identified in vapors produced at high temperature from a gold-titanium alloy. The homogeneous equilibria AuTi(g) = Au(g) + Ti(g) (direct dissociation) and AuTi(g) + Au(g) = Au2(g) + Ti(g) (isomolecular exchange) were studied by Knudsen effusion mass spectrometry in the temperature range 2111-2229K. The so determined equilibrium constants were treated by the "third-law method" of thermodynamic analysis, integrated with theoretical calculations, and the dissociation energy at 0K was derived as D0K ° (AuTi) = 241.0 ± 5.2 kJ/mol. A similar investigation was carried out for the AuSc and AuFe species, whose dissociation energies were previously reported with large uncertainties. The direct dissociation and the isomolecular exchange with the Au2 dimer were studied in the 1969-2274 and 1842-2092K ranges for AuSc and AuFe, respectively, and the dissociation energies derived as D0K ° (AuSc) = 240.4 ± 6.0 and D0K ° (AuFe) = 186.2 ± 4.2 kJ/mol. The experimental bond energies are compared with those calculated here by coupled cluster with single, double, and perturbative triple excitations with the correlation-consistent basis sets cc-pVXZ(-PP) and cc-pwCVXZ(-PP) (with X = T, Q, 5), also in the limit of complete basis set, and with those from complete active space self-consistent field-multi-reference configuration interaction calculations, recently available in the literature. The stronger bond of AuTi compared to AuFe parallels the trend observed in monochlorides. This analogy is shown to be more generally observed in the AuM and MCl diatomic series (with M = first row transition metal), in accordance with a picture of "pseudo-halogen" bonding behavior of gold.

Multiconfiguration Dirac–Hartree–Fock and Relativistic Many Body Perturbation Theory calculations of energy levels, wavelengths, weighted oscillator strengths, transitions rates, lifetimes, isotope shifts, hyperfine interaction constants and Landé g-factors of Zr XXXIX

An extensive and accurate data set of energy levels, wavelengths, weighted oscillator strengths, transitions rates, lifetimes, isotope shifts, hyperfine interaction constants and Landé g-factors have been calculated for the lowest 71 odd and even parity states arising from the 1s2 and 1snl(n=1−6,0≤l≤n−1) configurations of helium-like Zr. Calculations were performed using the Multiconfigurational Dirac–Hartree–Fock​ (MCDHF) followed by the Relativistic Configuration Interaction (RCI) method. Although no measurements or other theoretical results are available for comparison, we have implemented parallel calculations using a Flexible Atomic Code (FAC) by introducing the Relativistic Many-Body Perturbation Theory (RMBPT) method. Transition rates for electric-multipole (dipole (E1), quadrupole (E2)) and magnetic-multipole (dipole (M1), quadrupole (M2)) have been also calculated. Breit interactions and quantum electrodynamics effects (QED) have been included as perturbations in extensive relativistic configuration interaction (RCI) calculations. The results arising from the two sets of calculations MCDHF/RCI and RMBPT are quite close. Almost all atomic data of helium-like Zr ion presented in this paper are calculated for the first time. We expect that our results can be used as a reference point for any further calculations of plasma processes (electron impact excitation, dielectronic recombination). Furthermore, our values can contribute to the NIST database by essentially providing the data for the lowest singly excited states of Zr XXXIX.

A comprehensive study of the radiative properties of NO—a first step toward a complete air opacity

In this paper we propose a methodology to calculate the radiative properties of the diatomic molecular constituents of air, and utilize the present approach to model the radiative properties of nitrogen monoxide, NO. We also investigate the important physics involved in calculating accurate radiative quantities for air, such as the Planck and Rosseland mean opacities, and emission and absorption coefficients, as well as the couplings accounted for in rovibrational calculations. Complete active space self-consistent field multi-reference configuration interaction (CAS-MRCI) calculations were performed in order to model the NO X 2Π, a 4Π, b 4Σ−, 12Σ+, 22Σ+, 32Σ+, G 2Σ−, B′2Δ, (C, B) 22Π, (H′, L) 32Π, and 12Φ adiabatic states, and calculate the respective molecular data. The γ X 2Π − A 2Σ+, ɛ X 2Π − D 2Σ+, β′ X 2Π − B′2Δ, ‘11 000 Å’ A 2Σ+ − D 2Σ+, ‘infrared’ X 2Π − X 2Π and X 2Π − (C, B) 22Π (δ and β) band systems are investigated in monochromatic spectra calculations, as well as the Ogawa a 4Π − b 4Σ− band and several other band systems. Several conclusions are drawn, such as the importance of including the Ogawa band, which has not been included in previous air radiative models or comprehensive line-list calculations, as well as the importance of performing coupled rovibrational line-list calculations in order to accurately calculate the Rosseland means. We also found that the additional band systems modeled here contribute significantly to the total Planck and Rosseland means.