State Interaction Approach Research Articles

Theoretical Study of Low-Lying Electronic States of PtX (X = F, Cl, Br, and I) Including Spin-Orbit Coupling.

The low-lying electronic states of platinum ions (Pt(+)) and platinum monohalides (PtX; X = F, Cl, Br, and I) are calculated using the multireference configuration interaction method with relativistic effective core potentials. The spin-orbit coupling is taken into account through the perturbative state-interaction approach. For the Ω states of PtX below 35000 cm(-1), the potential energy curves and the corresponding spectroscopic constants are reported. It is found that the lowest Ω = 3/2 state is the ground one for the four species of PtX. Overall, the theoretical results are in reasonable agreement with the available experimental data.

Extensive ab initio study of the electronic states of BSe radical including spin–orbit coupling

The internally contracted multi-reference configuration interaction method (MRCI) with Davidson modification and the Douglas–Kroll scalar relativistic correction has been used to calculate the BSe molecule at the level of aug-cc-pV5Z basis set. The calculated electronic states, including 9 doublet and 6 quartet Λ-S states, are correlated to the dissociation limit of B(2Pu)+Se(3Pg) and B(2Pu)+Se(1Dg). The Spin-orbit coupling (SOC) interaction is taken into account via the state interaction approach with the full Breit-Pauli Hamiltonian operator, which causes the entire 15 Λ-S states to split into 32Ω states. This is the first time that the spin-orbit coupling calculation has been carried out on BSe. The potential energy curves of the Λ-S and Ω electronic states are depicted with the aid of the avoided crossing rule between electronic states of the same symmetry. The spectroscopic constants of the bound Λ-S and Ω states were determined, which are in good agreement with the experimental data. The transition dipole moments (TDMs) and the Franck-Condon factors (FCs) of the transitions from the low-lying bound Ω states A2Π(I)3/2, B2Π(I)1/2 and C2Δ(I)3/2 to the ground state X2Σ+1/2 have also been presented. Based on the previous calculations, the radiative lifetimes of the A2Π(I)3/2, B2Π(I)1/2 and C2Δ(I)3/2 were evaluated.

Ground and excited states of [Be–Xe]+: A multireference configuration interaction study

Potential energy curves (PECs) for the first three dissociation channels of [Be–Xe]+ have been calculated at the MRCI level of theory with Davidson and relativistic correction. Spin–orbit coupling is considered by the state interaction approach using the full Breit-Pauli Hamiltonian to analyze the interactions between Σ and Π electronic states in PECs crossing regions. Curves avoided crossings must be considered for A2Π and 22Π, 22Σ+ and 32Σ+ states to accurately estimate of spectroscopic parameters. Based on the PECs, spectroscopic parameters are determined. Finally, the transition dipole moments and radiative lifetimes of all possible transitions are predicted for future laboratory researches.

Extensive ab initio calculation on low-lying excited states of SiN+ cation including spin-orbit coupling

Electronic structures and transition properties of the SiN+ molecule are investigated by performing ab initio calculations based on scalar relativistic multireference configuration interaction (MRCI) method plus Davidson correction (+Q). The potential energy curves (PECs) for the 22 Λ-S electronic states of the SiN+ are obtained. The spectroscopic constants of the bound states are determined, where good agreements with the available spectroscopic data are achieved. Spin-orbit coupling (SOC) effect is introduced via the state interaction approach with the full Breit-Pauli Hamiltonian operator for the state X3 Σ −, a 3 Π, 5 Σ − and 5 Π. This is the first time that SOC calculation has been carried out on the SiN+. The four states split into 15 Ω states after the consideration of the SOC effect. The SOC effect, leading to some avoided crossings, is found to be substantial for the SiN+. Moreover, the transition dipole moments (TDMs) and Franck-Condon factors are derived. Finally, the corresponding radiative lifetimes of the a 3 Π 1 state are evaluated.

Ab initio study of the low-lying electronic states of [Be–Kr

The potential energy curves of the seven Ω states generated from the X2Σ+, 22Σ+, 32Σ+, A2Π and 22Π Λ–S states correlating with the first three dissociation channels of [Be–Kr]+ are calculated using the internally contracted multireference configuration interaction method with Davidson correction and relativistic correction. The spin–orbit coupling is computed using the state interaction approach with Breit–Pauli Hamiltonian. Based on the calculated potential energy curves, a set of spectroscopic constants are determined. Finally, the transition dipole moments and radiative lifetimes of transitions from all the Ω excited states to ground state are predicted for future laboratory research.

Theoretical spectroscopic calculations on the 25 Λ–S and 66 Ω states of [formula omitted] cation in the gas phase including the spin–orbit coupling effect

The potential energy curves (PECs) of 66 Ω states generated from the 25 Λ–S states are studied in detail with an ab initio quantum chemical method. All these 25 Λ–S states correlate to the first three dissociation limits of the N2+ cation, of which only the 16Σu+ is the repulsive and only the A2Πu, D2Πg, f4Πu and 12Φg are the inverted ones with the spin–orbit coupling included. The PECs are calculated for internuclear separations from about 0.10 to 1.10nm by the CASSCF method, which is followed by the internally contracted MRCI approach with Davidson correction. The spin–orbit coupling is accounted for by the state interaction approach with the Breit–Pauli Hamiltonian using an all-electron aug-cc-pCV5Z basis set. The convergent behavior is discussed with respect to the basis set and level of theory. Core–valence correlation corrections are included by using an aug-cc-pCV5Z basis set. Scalar relativistic corrections are calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. All these PECs are extrapolated to the complete basis set limit. With these PECs, the spectroscopic parameters of 24 Λ–S and 63 Ω bound states are evaluated by fitting the first ten vibrational levels whenever available, which are determined by solving the rovibrational Schrödinger equation with the Numerov׳s method. The energy splitting in the A2Π Λ–S state is determined to be 72.67cm−1, which agrees favorably with the measurements of 75.07cm−1. Moreover, other spectroscopic parameters of Λ–S and Ω states involved here are also in fair agreement with available measurements. It demonstrates that the spectroscopic parameters reported in this paper can be expected to be reliably predicted ones.

Accurate calculations of spectroscopic properties for the 13 Λ–S states and the 23 Ω states of BO radical including the spin–orbit coupling effect

The spectroscopic properties of 23 Ω states generated from the 13 Λ–S states of BO radical are studied for the first time for internuclear separations from about 0.07 to 1.0nm. Of the 13 Λ–S states, each of the F2Π, 12Φ and 12Δ states is found to possess the double well. Each of the 14Π, C2Π, 12Σ− and 22Σ− states possesses one well with one barrier. The A2Π, 14Π and F2Π are the inverted states with the spin–orbit coupling effect taken into account. All the states possess the deep well except for the 12Φ. The potential energy curves (PECs) are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. Core–valence correlation and scalar relativistic corrections are included into the calculations. The PECs are extrapolated to the complete basis set limit. The spin–orbit coupling effect is accounted for by the state interaction approach with the Breit–Pauli Hamiltonian. The spectroscopic parameters are evaluated, and compared with the available measurements and other theoretical results. The Franck–Condon factors and radiative lifetimes of the transitions from the B2Σ+, C2Π, D2Σ+, 12Σ− and 14Π Λ–S states to the ground state are calculated for several low vibrational levels, and some necessary discussion is made. Analyses show that the spectroscopic parameters reported in this paper can be expected to be reliably predicted ones.

Accurate calculations on 12 Λ–S and 28 Ω states of BN+ cation: Potential energy curves, spectroscopic parameters and spin–orbit coupling

The potential energy curves (PECs) of 28Ω states generated from the 12 states (X4Σ−, 12Π, 12Σ−, 12Δ, 12Σ+, 22Π, A4Π, B4Σ−, 32Π, 16Σ−, 22Σ− and 16Π) of the BN+ cation are studied for the first time for internuclear separations from about 0.1 to 1.0nm using an ab initio quantum chemical method. All the Λ–S states correlate to the first four dissociation channels. The 16Σ−, 32Π and A4Π states are found to be the inverted ones. The 12Σ+, 22Π, 32Π and 22Σ− states are found to possess the double well. The PECs are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. Core–valence correlation correction is included by a cc-pCV5Z basis set. Scalar relativistic correction is calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. The convergent behavior of present calculations is discussed with respect to the basis set and level of theory. The spin–orbit coupling is accounted for by the state interaction approach with the Breit–Pauli Hamiltonian using the all-electron cc-pCV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are obtained, and the vibrational properties of 12Σ+, 22Π, 32Π and 22Σ− states are evaluated. Analyses demonstrate that the spectroscopic parameters reported here can be expected to be reliably predicted ones. The conclusion is gained that the effect of spin–orbit coupling on the spectroscopic parameters are not obvious almost for all the Λ–S states involved in the present paper.

Theoretical studies on 14 Λ-S and 30 Ω states of BeBr molecule: potential energy curves, spectroscopic parameters and spin–orbit couplings

Using the complete active space self-consistent field (CASSCF) method followed by the internally contracted multi-reference configuration interaction (MRCI) approach in combination with the correlation-consistent basis sets, this paper studies the potential energy curves of X2Σ+, 22Σ+, 32Σ+, 12Σ−, A2Π, 22Π, 32Π, 12Δ, 14Σ+, 24Σ+, 14Σ−, 14Π, 24Π and 14Δ Λ-S states of BeBr molecule and the corresponding 30 Ω states for the first time. All the Λ-S states correlate to the first two dissociation channels, Be(1Sg) + Br(2Pu) and Be(3Pu) + Br(2Pu), of BeBr molecule. Of these Λ-S states, the 32Π and 24Π are found to be repulsive without the spin–orbit coupling, whereas 14Π, 24Π, 32Π and 24Σ+ are found to be repulsive with the spin–orbit coupling included. A2Π and 22Σ+ possess the double well whether the spin–orbit coupling effect is included or not. Only 14Σ+, 14Σ−, 12Π and 22Π are found to be the inverted Λ-S states. The spin–orbit coupling is accounted for by the state interaction approach with Breit–Pauli Hamiltonian using the all-electron cc-pCVTZ basis set. The potential energy curves determined by the internally contracted MRCI method are corrected for size-extensivity errors by means of the Davidson correction. Core–valence correlation correction is calculated with a cc-pCVTZ basis set. Scalar relativistic correction is included using the third-order Douglas–Kroll Hamiltonian approximation at the level of cc-pVTZ basis set. The spectroscopic parameters of all the Λ-S and Ω bound states are evaluated. The spectroscopic parameters are compared with those reported in the literature. Fair agreement is found between the present results and available measurements. In particular, the energy splitting of 204.43 cm−1 in the A2Π Λ-S state agrees well with the measurements of 201 cm−1. Analyses demonstrate that the spectroscopic parameters reported here can be expected to be reliably predicted ones.

Theoretical calculations on 12 Λ-S and 23 Ω states of CBr+ cation in the gas phase: Potential energy curves, spectroscopic parameters and spin–orbit coupling

The potential energy curves (PECs) of X1Σ+, a3Π, 13Σ+, 13Δ, 11Δ, 11Σ−, 13Σ−, 11Π, 21Σ+, 23Π, 21Π and 23Σ+ Λ-S states of CBr+ cation and corresponding 23 Ω states are calculated for the first time using the CASSCF method, which is followed by the internally contracted MRCI approach with the aug-cc-pVQZ basis set. All the Λ-S states involved are found to be bound and dissociate into the first dissociation limit of CBr+ cation. Of these Λ-S states, only the 13Σ+ and 13Σ− are inverted ones. The spin–orbit (SO) coupling is accounted for by the state interaction approach with the Breit–Pauli Hamiltonian. Core–valence correlation is included by a cc-pCVTZ basis set. Relativistic correction is calculated with the third-order Douglas–Kroll Hamiltonian approximation at the level of cc-pVQZ basis set. To obtain more reliable results, the PECs obtained by the MRCI calculations are corrected for size-extensivity errors by means of the Davidson modification. The PEC crossings of different Λ-S states are studied. With these PECs, the spectroscopic parameters of all the Λ-S and Ω states involved are obtained by fitting the first ten vibrational levels whenever available, which are calculated by solving the rovibrational Schrödinger equation using the Numerov's method. The spectroscopic parameters are compared with those reported in the literature. Excellent agreement is found between the present results and available measurements. In particular, the energy separation of 352.26cm−1 between the a3Π0+ and the a3Π1 Ω states agrees well with the measurements of 369±8cm−1, and the ωe results of 907.45 and 907.08cm−1 for the a3Π0+ and a3Π1 Ω states are in excellent agreement with the measurements of 906±2 and 903±6cm−1, respectively. These show that the spectroscopic parameters obtained in the present paper can be expected to be reliable predicted ones.

Ab initio calculation on the low-lying excited states of [formula omitted] cation including spin–orbit coupling

Ab initio all-electron relativistic calculations of the low-lying excited states of Si2+ have been performed at MRCI+Q/AVQZ level. The calculated electronic states, including 12 doublet and 12 quartet Λ–S states, are correlated to the dissociation limit of Si(3Pg)+Si+(2Pu). Spin–orbit interaction is taken into account via the state interaction approach with the full Breit-Pauli Hamiltonian, which causes the entire 24 Λ–S states to split into 54Ω states. This is the first time that spin–orbit coupling (SOC) calculation has been performed on Si2+. The obtained potential energy curves (PECs) of Λ–S and Ω states are respectively depicted with the aid of the avoided crossing rule between the same symmetry. The spectroscopic constants of the bound Λ–S and Ω states are determined, and excellent agreements with the latest theoretical results are achieved.

Accurate calculations on 9 Λ-S and 28 Ω states of NSe radical in the gas phase: Potential energy curves, spectroscopic parameters and spin–orbit couplings

The potential energy curves (PECs) of 28 Ω states generated from 9 Λ-S states (X2Π, 14Π, 16Π, 12Σ+, 14Σ+, 16Σ+, 14Σ-, 24Π and 14Δ) are studied for the first time using an ab initio quantum chemical method. All the 9 Λ-S states correlate to the first two dissociation limits, N(4Su)+Se(3Pg) and N(4Su)+Se(3Dg), of NSe radical. Of these Λ-S states, the 16Σ+, 14Σ+, 16Π, 24Π and 14Δ are found to be rather weakly bound states. The 12Σ+ is found to be unstable and has double wells. And the 16Σ+, 14Σ+, 14Π and 16Π are found to be the inverted ones with the SO coupling included. The PEC calculations are made by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson modification. The spin–orbit coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian. The convergence of the present calculations is discussed with respect to the basis set and the level of theory. Core-valence correlation corrections are included with a cc-pCVTZ basis set. Scalar relativistic corrections are calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The variation with internuclear separation of spin–orbit coupling constants is discussed in brief for some Λ-S states with one shallow well on each PEC. The spectroscopic parameters of 9 Λ-S and 28 Ω states are determined by fitting the first ten vibrational levels whenever available, which are calculated by solving the rovibrational Schrödinger equation with Numerov’s method. The splitting energy in the X2Π Λ-S state is determined to be about 864.92cm−1, which agrees favorably with the measurements of 891.80cm−1. Moreover, other spectroscopic parameters of Λ-S and Ω states involved here are also in fair agreement with available measurements. It demonstrates that the spectroscopic parameters reported here can be expected to be reliable predicted ones.

Accurate theoretical study on 18 Λ-S and 50 Ω states of CS in the gas phase: Potential energy curves, spectroscopic parameters, and spin-orbit coupling

The potential energy curves (PECs) of 50 Ω states generated from the 18 Λ-S states are studied for the first time using the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson modification. All the 18 Λ-S states correlate to the first dissociation limit, C((3)Pg) + S((3)Pg), of CS molecule, of which only the 2(5)Π is repulsive and the A(1)Π, A(') (1)Σ(+), and 2(3)Σ(+) possess double wells. The spin-orbit (SO) coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian. Core-valence correlation correction is taken into account with an all-electron cc-pCV5Z basis set. Scalar relativistic correction calculations are made by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pVTZ basis set. All the PECs are extrapolated to the complete basis set limit. The a(') (3)Σ(+), e(3)Σ(-), 1(5)Σ(+), 1(5)Π, and d(3)Δ are found to be the inverted Λ-S states with the SO coupling included. The spectroscopic parameters of 17 Λ-S and 41 Ω bound states are evaluated. The comparisons between the present results and available measurements are performed, and excellent agreement has been found. It shows that the spectroscopic results reported here can be expected to be reliable predicted ones.

Calculations on thirteen Λ–S states of PO radical: Electronic structure, spectroscopy and spin–orbit coupling

This paper presents the potential energy curves (PECs) of X2Π, B2Σ+, B′2Π, C2Σ−, C′2Δ, 32Π, a4Π, b4Σ−, 14Δ, 24Δ, 14Σ+, 16Σ+ and 16Π Λ–S states and the PECs of 16 Ω states generated from the eight bound Λ–S states of PO radical. All the PECs are calculated by the CASSCF method, which is followed by the internally contracted MRCI approach with the Davidson modification. The spin–orbit coupling is included by the state interaction approach with the Breit–Pauli Hamiltonian. The convergent behavior is observed and discussed with respect to the correlation-consistent basis set and level of theory. The effect on the energy splitting by core-electron correlations is studied. To improve the quality of PECs, core-valence correlation corrections are included by a cc-pCVTZ basis set. Scalar relativistic correction calculations are made by the third-order Douglas–Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. All the PECs are extrapolated to the complete basis set limit. With these PECs, the spectroscopic parameters of 10 Λ–S and 16 Ω bound states are evaluated. The vibrational manifolds of the first 16 vibrational states are evaluated for each Λ–S and Ω state of non-rotation radical. With the PECs obtained by the MRCI+Q/CV+DK+56+SO calculations, the SO coupling splitting energy of X2Π Λ–S state is determined as 225.18cm−1, which agrees well with the measurements of 224.17cm−1. Moreover, other spectroscopic parameters and molecular constants calculated here are also in excellent agreement with the available measurements. It shows that the spectroscopic parameters and molecular constants reported here can be expected to be reliable predicted ones.

Electronically excited-state properties and predissociation mechanisms of phosphorus monofluoride: A theoretical study including spin–orbit coupling

The 51 Ω states generated from the 22 Λ - S states of phosphors monofluoride have been investigated using the valence internally contracted multireference configuration interaction method with the Davidson correction and the entirely uncontracted aug-cc-pV5Z basis set. The spin-orbit coupling is computed using the state interaction approach with the Breit-Pauli Hamiltonian. Based on the calculated potential energy curves, the spectroscopic constants of the bound and quasibound Λ - S and Ω states are obtained, and very good agreement with experiment is achieved. Several quasibound states caused by avoided crossings are found. Various curve crossings and avoided crossings are revealed, and with the help of our computed spin-orbit coupling matrix elements, the predissociation mechanisms of the a(1)Δ, b(1)Σ(+), e(3)Π, g(1)Π, and (3)(3)Π states are analyzed. The intricate couplings among different electronic states are investigated. We propose that the avoided crossing between the A(3)Π(0 +) and b(1)Σ(0+) (+) states may be responsible for the fact that the A(3)Π ν' ≥ 12 vibrational levels can not be observed in experiment. The transition properties of the A(3)Π - X(3)Σ(-) transition are studied, and our computed Franck-Condon factors and radiative lifetimes match the experimental results very well.

Ab initio calculation on the low-lying excited states of BCl radical

The internally contracted multi-reference configuration interaction method (MRCI) is used to calculate 22 Λ–S electronic states of BCl radical at the level of aug-cc-pVQZ basis set, where Davidson modification with the Douglas–Kroll scalar relativistic correction is also taken into account. This is the first time multi-reference configuration calculation on the excited state of BCl radical. Spin–orbit coupling effect is introduced by the state interaction approach with the full Breit–Pauli Hamiltonian operator for the two lowest excited and ground Λ–S states. The potential energy curves of the Λ–S and Ω electronic states are depicted according to the avoided crossing rule of the same symmetry. The spectroscopic constants for the bound Λ–S and Ω states are fitted, which are in good agreement with the corresponding observed values. The calculated excitation energy separation of a3Π0−−a3Π0+ is only 0.22cm−1, while the energy intervals of a3Π0+−a3Π1 and a3Π1−a3Π2 are 47.85cm−1 and 48.06cm−1, respectively. In addition, transition dipole moments (TDMs) followed by Franck–Condon factors and radiative lifetimes for the transitions from a3Π0+, a3Π1 and A1Π1 to the ground state X1∑0++ are predicted as well.

Investigations on spectroscopic parameters and molecular constants of SO+ (b4∑-) cation

The potential energy curve (PEC) of b4Σ- electronic state of the SO+ cation is calculated using the internally contracted multireference configuration interaction approach with the Davidson modification (MRCI+Q) for internuclear separations from 0.103 to 1.083 nm. The basis set used is a correlation- consistent aug-cc-pV5Z basis set. The spin-orbit coupling effect on the spectroscopic parameters is taken into account by the state interaction approach with the full Breit-Pauli operator with all-electron basis set, aug-cc-pCVTZ. To improve the quality of PEC and spin-orbit coupling constant, core-valence correlation and relativistic corrections are included. Core-valence correlation correction is calculated using a cc-pCVTZ basis set. Relativistic corrections are included by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. At the MRCI+Q/aug-cc-pV5Z+CV+DK level, the spin-orbit coupling constant of the SO+ (b4Σ-1/2,3/2) is 1 cm-1 when the aug-cc-pCVTZ basis set is used for the spin-orbit coupling calculations The spectroscopic parameters are determined and compared with those reported in the literature. Excellent agreement is found between the present results and the measurements. The vibrational level G(v) inertial rotation constant Bv and centrifugal distortion constant Dv are predicted for each vibrational state of the b4Σ- electronic state by solving the ro-vibrational Schrödinger equation of nuclear motion using Numerov's method and those of the first 2 vibrational states are reported for the non-rotation SO+ cation. Comparison with the measurements demonstrates that the present vibrational manifolds are both reliable and accurate. They should be good predictions for future experimental or theoretical research.

Spin-orbit effects in the ground X2Π state and two low-lying excited valence states B2Π and L′2Φ for NO

The potential energy curves and spectroscopic constants B e , ω e , ω e χ e , α e , D e of the six Ω states (X 2Π1/2, 3/2, B 2Π1/2, 3/2 and L ′2Φ5/2, 7/2) of the NO radical molecule were calculated using spin-orbit multi-configuration quasi-degenerate perturbation theory (SO-MCQDPT). The spin-orbit coupling effect was considered via the state interaction approach with the full Breit-Pauli Hamiltonian. The spin-orbit splitting energy between the X 2Π1/2 and X 2Π3/2 states of the NO radical is 129.61 cm-1, which agrees reasonably well with the experimental value of 123.13 cm-1. For the B 2Π1/2, 3/2 states, the spin-orbit coupling (SOC) splitting energy is 35.99 cm-1, the corresponding experimental value is 31.7 cm-1. The SOC splitting value of the L ′2Φ5/2, 7/2 states was calculated to be 103.2 cm-1. The spectroscopic constants R e , ω e , ω e χ e , B e , α e , D e are in reasonable agreement with available experimental and theoretical data for the six Ω states.

Calculation of X-ray photoelectron spectra with the use of the normalized elimination of the small component method

A method for the calculation of X-ray photoelectron spectra (XPS) based on the use of the normalized elimination of the small component (NESC) formalism combined with the restricted active space state interaction (RASSI) approach with atomic mean field integrals (AMFI) is developed. Benchmark calculations carried out for the 4f XPS of U5+show that the NESC/RASSI/AMFI method is capable of reproducing the results of the full 4-component relativistic calculations with excellent accuracy. The NESC/RASSI/AMFI method is applied to study the 4p and 5p XPS of ytterbium phosphide YbP. The results of the calculations suggest an alternative interpretation of the satellite peaks in the 4p XPS of YbP.

Extensive theoretical study on electronically excited states and predissociation mechanisms of sulfur monoxide including spin–orbit coupling

The potential energy curves of the 69 Ω states generated from the 24 Λ-S states of sulfur monoxide are calculated for the first time using the internally contracted multireference configuration interaction method with the Davidson correction and the entirely uncontracted aug-cc-pV5Z basis set. Spin-orbit coupling is taken into account by the state interaction approach with the full Breit-Pauli Hamiltonian. Very good agreement is achieved between our computed spectroscopic properties and the available experimental data. The transition properties of the B(3)Σ(-) -X(3)Σ(-) and (4)1-X0(+) transitions are predicted, and our computed Franck-Condon factors and radiative lifetimes match the experimental results very well. The predissociation mechanisms are investigated, and various new predissociation channels are located. We present a new interpretation on the breaking-off of the rotational levels of the B(3)Σ(-) lower vibrational states observed in experiment, and propose that the predissociation is induced by the Coriolis coupling between the B(3)Σ(-) rovibrational levels and the A(3)Π state. Our calculations indicate that, at ν' = 9, the B(3)Σ(-) state predissociates via the C(3)Π state; around ν' = 14, three spin-orbit-induced predissociation pathways via (1)(5)Σ(+) , (2)(5)Π, and e(1)Π would be open; around ν' = 17, the pathways via (2)(1)Σ(+) , (2)(3)Σ(+) and (2)(5)Σ(+) would contribute. These satisfactorily explain the experimental results about the diffuseness of the B(3)Σ(-) bands. Furthermore, various predissociation pathways of the C'(3)Π state are predicted, through which the C'(3)Π state could predissociate rapidly.