TY - JOUR
T1 - Intralines of quasi-conical intersections on torsion planes
T2 - Methylamine as a case study
AU - Levi, C.
AU - Halász, G. J.
AU - Vibók, Á
AU - Bar, I.
AU - Zeiri, Y.
AU - Kosloff, R.
AU - Baer, M.
PY - 2009/6/18
Y1 - 2009/6/18
N2 - Recently we reported on a novel feature associated with the intersection of the two lowest states1A and 1A" of the methylamine (J. Chem. Phys. 2008, 128, 244302). We established the existence of a finite (closed) line of conical intersections (ci), namely, a finite seam, located in the HC-NHH symmetry plane, a line that is formed by moving a single hydrogen on that plane while locking the positions of the (six) other atoms. In the present article, this study is extended to the corresponding torsion planes formed by rotating the methyl group around the CN axis. The torsion planes, in contrast with the HC-NHH symmetry plane, do not satisfy the symmetry feature that enables the seam just mentioned. Nevertheless, the calculated nonadiabatic coupling terms (NACTs) resemble features similar to those encountered in the HC-NHH symmetry plane. Following a tedious numerical study supported by a theoretical model (Section III), it was verified that these NACTs may become similar to those on the symmetry plane, sometimes even to the level of almost no distinction, but lack one basic feature; namely, they are not singular and therefore do not form topological effects.
AB - Recently we reported on a novel feature associated with the intersection of the two lowest states1A and 1A" of the methylamine (J. Chem. Phys. 2008, 128, 244302). We established the existence of a finite (closed) line of conical intersections (ci), namely, a finite seam, located in the HC-NHH symmetry plane, a line that is formed by moving a single hydrogen on that plane while locking the positions of the (six) other atoms. In the present article, this study is extended to the corresponding torsion planes formed by rotating the methyl group around the CN axis. The torsion planes, in contrast with the HC-NHH symmetry plane, do not satisfy the symmetry feature that enables the seam just mentioned. Nevertheless, the calculated nonadiabatic coupling terms (NACTs) resemble features similar to those encountered in the HC-NHH symmetry plane. Following a tedious numerical study supported by a theoretical model (Section III), it was verified that these NACTs may become similar to those on the symmetry plane, sometimes even to the level of almost no distinction, but lack one basic feature; namely, they are not singular and therefore do not form topological effects.
UR - http://www.scopus.com/inward/record.url?scp=67049145830&partnerID=8YFLogxK
U2 - 10.1021/jp901072u
DO - 10.1021/jp901072u
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C2 - 19462985
AN - SCOPUS:67049145830
SN - 1089-5639
VL - 113
SP - 6756
EP - 6762
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 24
ER -