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Pandey RK, Srikanth K, Tripathi SS, Rajagopala Rao T. Resolving the Experimental Photoelectron Spectra of CAl 3Si . J Phys Chem A 2024; 128:355-369. [PMID: 38189257 DOI: 10.1021/acs.jpca.3c06295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The experimental photoelectron spectra concerning the six electronic states of CAl3Si- are resolved through electronic structure calculations and quantum nuclear dynamics in this study. It incorporates a model diabatic Hamiltonian to evaluate the coupling parameters and fit the potential energy curves (PECs). The analysis of these PECs showed us that there are sufficient nonadiabatic effects in the photoelectron spectra through the presence of various conical intersections. Poisson intensity distributions (PIDs) and the wave packet density plots are utilized for assigning the fundamental and first overtone excitations. The nuclear dynamics study is accomplished by employing time-dependent (TD) and time-independent (TI) quantum chemistry methods. Ultimately, our theoretical results concurred well with the experimental findings exhibiting vibronic coupling amidst the nearly positioned electronic states.
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Affiliation(s)
- Rishabh Kumar Pandey
- Department of Chemistry, Indian Institute of Technology Patna, Bihta 801106, India
| | - Korutla Srikanth
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
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2
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Pandey RK, Srikanth K, Tak A, Kumar A, Rao TR. A theoretical study of vibronic coupling in the photoelectron spectra of Al 6N . Phys Chem Chem Phys 2023; 25:12990-13003. [PMID: 37165932 DOI: 10.1039/d3cp00836c] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This work emphasizes the appearance of non-adiabatic effects in the photoelectron spectra of Al6N-. It includes ab initio electronic structure calculations obtained on the first seven low-lying electronic states of Al6N- and a nuclear dynamics study utilizing time-dependent and time-independent quantum chemistry approaches. A model vibronic Hamiltonian is constructed in a diabatic electronic representation to estimate the coupling parameters corresponding to the fifteen vibrational modes of Al6N-. Theoretical spectral bands are achieved by employing the vibronic coupling theory followed by reduced dimensional calculations to understand the role of individual vibrational modes in the overall photoelectron spectra. Finally, the theoretically obtained photodetachment spectra show good agreement with the experimental spectra revealing vibronic coupling among the closely spaced spectral bands.
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Affiliation(s)
- Rishabh Kumar Pandey
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
| | - Korutla Srikanth
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
| | - Anuj Tak
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
| | - Abhishek Kumar
- Indian Association for Cultivation of Science, Kolkata, West Bengal, 700032, India
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Srikanth K, Kumar A, Tammineni RR. Unraveling the Photoelectron Spectrum of 1-Phospha-2,3,4-triazolate Anion, HCPN 3-, A Theoretical Approach. J Phys Chem A 2023; 127:78-91. [PMID: 36563286 DOI: 10.1021/acs.jpca.2c06701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The first five low-lying electronic states of HCPN3 are probed through extensive ab initio electronic structure and quantum dynamics studies to reproduce the 193 nm photoelectron spectrum. Vibronic Hamiltonian is constructed and availed for time-dependent (TD) and time-independent (TI) quantum dynamical studies. The presence of numerous conical intersections (CIs) and crossings among electronic states yielded interesting nonadiabatic effects in the photoelectron bands of the overall spectrum. Moreover, the theoretical bands corresponding to five electronic states have reproduced all three experimental spectral bands. Among these, the first two bands originated due to a combination of four electronic states as predicted by previous studies. The third band corresponds to the fifth electronic state. The results calculated via TD and TI approaches exhibited satisfying agreement with the experimental results.
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Affiliation(s)
- Korutla Srikanth
- Department of Chemistry, Indian Institute of Technology Patna, Patna801106, India
| | - Abhishek Kumar
- Department of Chemistry, Indian Institute of Technology Patna, Patna801106, India
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Lu SJ. B8C10: A C2v planar polycyclic structure bridged by the central strong C C bond and strengthened by the aromaticity. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Kumar A, Srikanth K, Sarkar K, Sarkar R, Rao TR. Understanding of the Photodetachment Spectrum of Anionic Mixed Carbon-Boron Cluster C 3B 5- Following Adiabatic and Nonadiabatic Quantum Chemistry Approaches. J Phys Chem A 2022; 126:4563-4576. [PMID: 35796655 DOI: 10.1021/acs.jpca.2c01683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The presence of nonadiabaticity in the photodetachment bands of the anionic mixed carbon-boron cluster C3B5- has been realized through ab initio electronic structure calculations and detailed analyses of quantum dynamics study on top of those electronic structures. In the course of our study, we traverse extensive first principles electronic structure calculations to compute potential energy curves and to trace the energetic locations for the conical intersections in the multidimensional surfaces. All the ab initio calculations are performed on the four low-lying electronic states of the C3B5 cluster, while quantum nuclear dynamics are pursued on those electronic states by applying both time-dependent and time-independent quantum chemistry frameworks. In particular, we rely on the diabatic electronic representation to construct the molecular Hamiltonian. Altogether, the simulated theoretical spectra offer exceptional agreement with the experimental attainments.
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Affiliation(s)
- Abhishek Kumar
- Department of Chemistry, Indian Institute of Technology Patna, Patna 801106, India
| | - Korutla Srikanth
- Department of Chemistry, Indian Institute of Technology Patna, Patna 801106, India
| | - Kanchan Sarkar
- Institut für Theoretische Chemie, Universität Ulm, 89081 Ulm, Germany
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B6C8 and its anion: a planar dodecagon reinforced by the central strong B−B single bond and aromaticity. Theor Chem Acc 2022. [DOI: 10.1007/s00214-022-02885-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
We have explored the chemical space of BAl4Mg−/0/+ for the first time and theoretically characterized several isomers with interesting bonding patterns. We have used chemical intuition and a cluster building method based on the tabu-search algorithm implemented in the Python program for aggregation and reaction (PyAR) to obtain the maximum number of possible stationary points. The global minimum geometries for the anion (1a) and cation (1c) contain a planar tetracoordinate boron (ptB) atom, whereas the global minimum geometry for the neutral (1n) exhibits a planar pentacoordinate boron (ppB) atom. The low-lying isomers of the anion (2a) and cation (3c) also contain a ppB atom. The low-lying isomer of the neutral (2n) exhibits a ptB atom. Ab initio molecular dynamics simulations carried out at 298 K for 2000 fs suggest that all isomers are kinetically stable, except the cation 3c. Simulations carried out at low temperatures (100 and 200 K) for 2000 fs predict that even 3c is kinetically stable, which contains a ppB atom. Various bonding analyses (NBO, AdNDP, AIM, etc.) are carried out for these six different geometries of BAl4Mg−/0/+ to understand the bonding patterns. Based on these results, we conclude that ptB/ppB scenarios are prevalent in these systems. Compared to the carbon counter-part, CAl4Mg−, here the anion (BAl4Mg−) obeys the 18 valence electron rule, as B has one electron fewer than C. However, the neutral and cation species break the rule with 17 and 16 valence electrons, respectively. The electron affinity (EA) of BAl4Mg is slightly higher (2.15 eV) than the electron affinity of CAl4Mg (2.05 eV). Based on the EA value, it is believed that these molecules can be identified in the gas phase. All the ptB/ppB isomers exhibit π/σ double aromaticity. Energy decomposition analysis predicts that the interaction between BAl4−/0/+ and Mg is ionic in all these six systems.
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Duran AT, Powis I, Holland DMP, Nicolas C, Bozek J, Trofimov AB, Grigoricheva EK, Skitnevskaya AD. Vibronic interaction in trans-dichloroethene studied by vibration- and angle-resolved photoelectron spectroscopy using 19–90 eV photon energy. J Chem Phys 2021; 154:094303. [DOI: 10.1063/5.0040049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ayse T. Duran
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
- Photek Ltd., Castleham Road, St. Leonards on Sea, East Sussex TN38 9NS, United Kingdom
| | - Ivan Powis
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - David M. P. Holland
- Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, United Kingdom
| | - Christophe Nicolas
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - John Bozek
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - A. B. Trofimov
- Laboratory of Quantum Chemical Modelling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
- Favorsky’s Institute of Chemistry, SB RAS, Favorsky Str. 1, 664033 Irkutsk, Russia
| | - E. K. Grigoricheva
- Laboratory of Quantum Chemical Modelling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - A. D. Skitnevskaya
- Laboratory of Quantum Chemical Modelling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
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Kumar A, Rao TR, Sarkar R. An unbiased confirmation of the participating isomers of C 2B 5- in the formation of its photo-detachment spectra: a theoretical study. Phys Chem Chem Phys 2021; 23:3160-3175. [PMID: 33498079 DOI: 10.1039/d0cp04619a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The primary goal of the present article is to provide an unbiased structural confirmation of C2B5-, relying on its available experimental photo-detachment spectra. The study is performed from scratch by optimizing the lowest energy isomers of C2B5- and later, suitable molecular vibronic Hamiltonians are constructed by analyzing the normal modes of these optimized isomers. The Hamiltonians' parameters are evaluated from the fits of the calculated ab initio single point energies using a state of the art multireference configuration (MRCI) level of theory employing a correlation consistent polarized triple zeta (cc-pVTZ) basis set. The state-averaged variant of the MRCI level of theory is also applied to deal with the highly interactive electronic states of both of the isomers. A detailed analysis of the potential energy curves along the totally symmetric vibrational modes is performed to understand the energy modulation between the different electronic states and also to find the energetic locations of the conical intersections. The introduction of the non-symmetric vibrational modes in the Hamiltonians help to understand the impact of non-adiabaticity during energy modulation in the coupled surfaces. Later, both adiabatic and non-adiabatic nuclear dynamics are performed on the electronic states of both of the isomers using the constructed reduced and full-dimensional Hamiltonians. The results of the adiabatic dynamics are used to assign the positions of the simulated photo-detachment bands, while the non-adiabatic dynamics improve the shape of those bands. Finally, we compare our theoretical findings with the available experimental photo-detachment spectra of C2B5- to provide an unbiased structural confirmation of the participating isomers of C2B5- in its photo-detachment spectra.
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Affiliation(s)
- Abhishek Kumar
- Department of Chemistry, Indian Institute of Technology, Patna, Bihta, Bihar, 801103, India.
| | - T Rajagopala Rao
- Department of Chemistry, Indian Institute of Technology, Patna, Bihta, Bihar, 801103, India.
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Trofimov AB, Skitnevskaya AD, Grigoricheva EK, Gromov EV, Köppel H. Vibronic coupling in the ground and excited states of the pyridine radical cation. J Chem Phys 2020; 153:164307. [DOI: 10.1063/5.0024446] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. B. Trofimov
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
- Favorsky’s Institute of Chemistry, SB RAS, Favorsky Str. 1, 664033 Irkutsk, Russia
| | - A. D. Skitnevskaya
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - E. K. Grigoricheva
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - E. V. Gromov
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany
- Max-Planck Institute for Medical Research, Jahnstraße 29, 69120 Heidelberg, Germany
| | - H. Köppel
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany
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Kumar A, Agrawal S, Rao TR, Sarkar R. Rationalization of photo-detachment spectra of the indenyl anion (C 9H 7-) from the perspective of vibronic coupling theory. Phys Chem Chem Phys 2019; 21:22359-22376. [PMID: 31577305 DOI: 10.1039/c9cp04594e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nuclear dynamics of the low-lying first four electronic states of the prototypical indenyl radical is investigated based on first principles calculations to rationalize the experimental vibronic structure of the radical. The study is performed following both time-dependent and time-independent quantum-chemistry approaches using a model diabatic Hamiltonian. The construction of model Hamiltonians is based on the fits of the adiabatic energies calculated from the electronic structure method. The analyses of the static and dynamics results of the present study corroborate the experimental findings regarding the shape of the spectrum, vibrational progressions and the lifetime of the excited state. Finally, the present theoretical investigations suggest that the electronic non-adiabatic effect is extremely important for a detailed study of the vibronic structure and the electronic relaxation mechanism of the low-lying electronic states of the indenyl radical.
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Affiliation(s)
- Abhishek Kumar
- Department of Chemistry, Indian Institute of Technology, Patna, Bihta, Bihar 801103, India.
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