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001-es BibID:	BIBFORM095756
035-os BibID:	(cikkazonosító)081106
Első szerző:	Halász Gábor J. (fizikus)
Cím:	Renner-Teller nonadiabatic coupling terms: An ab-initio study of the HNH molecule / G. J. Halász, Á. Vibók, R. Baer, M. Baer
Dátum:	2006
ISSN:	0021-9606
Megjegyzések:	In this Communication we present the first theoretical/numerical treatment of nonadiabatic coupling terms (NACT) that originate from the Renner-Teller (RT) model, namely, those that follow from the splitting of an electronic level of a linear molecule when it becomes bent. These two newly formed states are characterized by different symmetries and are designated as A and B. Our main findings: (1) The RT NACTs are quantized as long as they are calculated close enough to collinear configuration of the molecule (in this case HNH). Their value is gamma = 1 (the Jahn-Teller values in similar situations, are gamma =1/2.) (2) Calculation of RT NACTs at bent configurations (i.e., at a distance from the linear axis yield decreased values, sometimes by more than 50%. This last finding implies that in strongly bent configurations the two-state Hilbert subspace (formed by the above mentioned A and B states) is affected by upper states, most likely via Jahn-Teller conical intersections. (3) This study has also important practical implications. The fact that the RT NACTs decrease in (strongly) bent situations implies that analyzing spectroscopic data employing only the two-states may not be sufficient in order to achieve the required accuracy.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Journal of Chemical Physics. - 124 : 8 (2006), p. 1-4. -
További szerzők:	Vibók Ágnes (1962-) (fizikus) Baer, Roi Baer, Michael
Pályázati támogatás:	T037994 OTKA M041537 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM085989
Első szerző:	Mebel, Alexander M.
Cím:	Quantization of the 3-3 nonadiabatic coupling matrix for three coupled states of the C2H molecule / A. M. Mebel, G. J. Halász, Á. Vibók, A. Alijah, M. Baer
Dátum:	2002
ISSN:	0021-9606
Megjegyzések:	The three ab initio nonadiabatic coupling terms related to the three strongly coupled states of the C2H molecule, i.e., 2 (2)A('), 3 (2)A('), and 4 (2)A('), were studied applying the line integral technique [M. Baer, Chem. Phys. Lett. 35, 112 (1975)]. The following was verified: (1) Due to the close proximity of the conical intersections between these three states, two-state quantization cannot always be satisfied between two successive states. (2) It is shown that in those cases where the two-state quantization fails a three-state quantization is satisfied. This three-state quantization is achieved by applying the 3x3 nonadiabatic coupling matrix that contains the three relevant nonadiabatic coupling terms. The quantization is shown to be satisfied along four different contours (in positions and sizes) surrounding the relevant conical intersections.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Journal of Chemical Physics. - 117 : 3 (2002), p. 991-1000. -
További szerzők:	Halász Gábor J. (1961-) (fizikus) Vibók Ágnes (1962-) (fizikus) Alijah, A. Baer, Michael
Pályázati támogatás:	FKFP 0498/2000 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM084910
Első szerző:	Vértesi Tamás (fizikus)
Cím:	On the peculiarities of the diabatic framework: New insight / Vértesi T., Vibók Á., Halász G. J., Baer M.
Dátum:	2004
ISSN:	0021-9606
Megjegyzések:	In this article we consider the electronic diabatic presentation of a two-state system with the aim of earning insight regarding the distribution of conical intersections in a given region. In this process we revealed explicit relationship between the diabatic potentials and the locations of conical intersections. The study is accompanied with numerical examples as worked out for a model and ab initio potential energy surfaces of the Na1H2 system.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Journal Of Chemical Physics. - 120 : 6 (2004), p. 2565-2574. -
További szerzők:	Vibók Ágnes (1962-) (fizikus) Halász Gábor J. (1961-) (fizikus) Baer, Michael
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM095755
035-os BibID:	(cikkazonosító)024312
Első szerző:	Vibók Ágnes (fizikus)
Cím:	Two-state versus three-state quantization: An ab initio study of the three lower states of the {N,H2?A?} system / Á. Vibók, G. J. Halász, S. Suhai, D. K. Hoffman, D. J. Kouri, M. Baer
Dátum:	2006
ISSN:	0021-9606
Megjegyzések:	In this article we present the first ab initio study of the conical intersections cis and their electronic nonadiabatic coupling terms NACTs for the (N,H2) system. Efforts were made to reveal the location of cis between the two lower, 1 2 A' and 2 2 A' states?to be designated as 1,2 cis?and the cis between the two upper, 2 2 A' and 3 2 A' states?to be designated as the 2,3 cis?of this system. We found that these cis are located along the collinear {NHH) arrangement. The study is carried out by analyzing two-state magnitudes such as the (1,2) and (2,3) adiabatic-to-diabatic transformation angles known also as the mixing angles and the corresponding topological phases known also as the Berry phases or the Longuet-Higgins phases. In addition, a detailed three-state study is carried out. Here the emphasis is on driving the diagonal elements of the topological D matrix and analyzing situations for which the corresponding nonadiabatic coupling matrix is quantized. The reliability of two-state results is carefully examined by comparing them with corresponding outcomes derived for the three-state study. In addition we also calculated the potential-energy surfaces related to the two lower states and studied to what extent they are affected by the (1,2) ci. The results obtained in this treatment were found to be in full agreement with the NACT's calculations.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Journal of Chemical Physics. - 124 : 2 (2006), p. 1-8. -
További szerzők:	Halász Gábor J. (1961-) (fizikus) Suhai Sándor Hoffman, D. K. Kouri, D. J. Baer, Michael
Pályázati támogatás:	T037994 OTKA M041537 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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