Simplified model to treat the electron attachment of complex molecules: Application to 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi>CN</mml:mi></mml:mrow></mml:math>
 and the quest for the 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>CN</mml:mi></mml:mrow><mml:mo>−</mml:mo></mml:msup></mml:math>
 formation mechanism

Yuen, Chi Hong; Douguet, Nicolas; Santos, Samantha Fonseca dos; Orel, A. E.; Kokoouline, Viatcheslav

doi:10.1103/physreva.99.032701

Cited by 11 publications

(10 citation statements)

References 66 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also observe a good agreement between our results and the MRCI+Q/cc-pVQZ calculations with eight active orbitals in the complete active space. 55 We now move on to discuss adiabatic excitation energies (AEEs) of B ̃2A 1 ← X ̃2B 2 and A ̃2B 1 ← X ̃2B 2 . The AEEs obtained from the DFT-SSMRPT method using DFT-CASCI optimized geometries are reported in Table 4.…”

Section: Resultssupporting

confidence: 89%

“…Schaefer and co-workers argued that the difference in the occupations of the 5a 1 and 2b 2 orbitals in the X̃ 2 B 2 and B̃ 2 A 1 states is primarily responsible for the large values of the ν 1 , ν 4 , and ν 5 vibrational modes in the B̃ 2 A 1 state compared to the ground X̃ 2 B 2 state. We also observe a good agreement between our results and the MRCI+Q/cc-pVQZ calculations with eight active orbitals in the complete active space …”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Description of the Methylene Amidogene Radical and Its Anion with an Economical Treatment of Correlation Effects Using Density Functional Theory Orbitals

Chaudhuri

Chattopadhyay

2021

J. Phys. Chem. A

View full text Add to dashboard Cite

The ground and low-lying excited state electronic structural properties (such as equilibrium geometries, harmonic frequencies, excitation energies, barrier energy, and so on) of the methylene amidogene radical (H2CN) and its anion (H2CN–) have been studied using the CASCI (complete active space configuration interaction) and SSMRPT (state-specific multireference Møller–Plesset perturbation theory) methods with density function theory (DFT) orbitals. Here, the span of the active orbitals have been obtained from Kohn–Sham DFT using B3LYP exchange-correlation functionals in the CASCI (DFT-CASCI) approximation to describe nondynamic correlation associated with electronic degeneracies. The DFT-SSMRPT protocol provides an attractive way to deal with both dynamical and nondynamical correlation effects in strongly correlated systems such as H2CN and H2CN–. The present work clearly indicates that the electronic absorption band near 35,050 cm–1 corresponds to the B̃2A1 ← X̃2B2 transition. DFT-SSMRPT findings are in close agreement with high-level theoretical estimates. It is concluded that the transition at 1725 cm–1 could be due to the CN stretching of the trans-HCNH isomer which is originally assigned to the CN stretch of H2CN in the experiment. The present results confirm most of the previous vibrational assignments. It is not possible to definitively assign a transition to the 35,600 cm–1 band with the present estimations, suggesting further experiment is urgently called for.

show abstract

Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Description of the Methylene Amidogene Radical and Its Anion with an Economical Treatment of Correlation Effects Using Density Functional Theory Orbitals

Chaudhuri

Chattopadhyay

2021

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“… 18 , 20 However, if the potential energy surfaces (PES) are constructed by single-point energy calculations and the nuclei are treated quantum mechanically, one is still limited to very few degrees of freedom. 24 − 29 …”

mentioning

confidence: 99%

“…A very accurate description of TAs and DEA is offered by nonlocal resonance theory, ,− but this entails high computational cost so that polyatomic molecules must be treated in reduced dimensionality considering only a few vibrational degrees of freedom . A local approximation is thus usually invoked, which is valid as long as one does not deal with very broad resonances or effects near the threshold. , However, if the potential energy surfaces (PES) are constructed by single-point energy calculations and the nuclei are treated quantum mechanically, one is still limited to very few degrees of freedom. − …”

mentioning

confidence: 99%

Ab Initio Molecular Dynamics of Temporary Anions Using Complex Absorbing Potentials

Gyamfi

Jagau

2022

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

Dissociative electron attachment, that is, the cleavage of chemical bonds induced by low-energy electrons, is difficult to model with standard quantum-chemical methods because the involved anions are not bound but subject to autodetachment. We present here a new computational development for simulating the dynamics of temporary anions on complex-valued potential energy surfaces. The imaginary part of these surfaces describes electron loss, whereas the gradient of the real part represents the force on the nuclei. In our method, the forces are computed analytically based on Hartree–Fock theory with a complex absorbing potential. Ab initio molecular dynamics simulations for the temporary anions of dinitrogen, ethylene, chloroethane, and the five mono- to tetrachlorinated ethylenes show qualitative agreement with experiments and offer mechanistic insights into dissociative electron attachments. The results also demonstrate how our method evenhandedly deals with molecules that may undergo dissociation upon electron attachment and those which only undergo autodetachment.

show abstract

“…However, the role of REA process, initially proposed as the dominant mechanism 4 , is still open to the debate [8][9][10][11][12][13] , in particular, the CN − abundance in IRC + 10216 predicted with statistics theory calculations indicated a significant deviation from the observation 8,13 . Recently, the contribution from the DEA to H 2 CN in IRC + 10216 was eliminated either 14 .…”

mentioning

confidence: 99%

Direct observation of long-lived cyanide anions in superexcited states

Gao

Xie

et al. 2021

Commun Chem

View full text Add to dashboard Cite

The cyanide anion (CN−) has been identified in cometary coma, interstellar medium, planetary atmosphere and circumstellar envelopes, but its origin and abundance are still disputed. An isolated CN− is stabilized in the vibrational states up to ν = 17 of the electronic ground-state 1Σ+, but it is not thought to survive in the electronic or vibrational states above the electron autodetachment threshold, namely, in superexcited states. Here we report the direct observation of long-lived CN− yields of the dissociative electron attachment to cyanogen bromide (BrCN), and confirm that some of the CN− yields are distributed in the superexcited vibrational states ν ≥ 18 (1Σ+) or the superexcited electronic states 3Σ+ and 3Π. The triplet state can be accessed directly in the impulsive dissociation of BrCN− or by an intersystem transition from the superexcited vibrational states of CN−. The exceptional stability of CN− in the superexcited states profoundly influences its abundance and is potentially related to the production of other compounds in interstellar space.

show abstract

Simplified model to treat the electron attachment of complex molecules: Application to H2CN and the quest for the CN− formation mechanism

Cited by 11 publications

References 66 publications

Description of the Methylene Amidogene Radical and Its Anion with an Economical Treatment of Correlation Effects Using Density Functional Theory Orbitals

Description of the Methylene Amidogene Radical and Its Anion with an Economical Treatment of Correlation Effects Using Density Functional Theory Orbitals

Ab Initio Molecular Dynamics of Temporary Anions Using Complex Absorbing Potentials

Direct observation of long-lived cyanide anions in superexcited states

Contact Info

Product

Resources

About