We present an ab initio study of the static Jahn-Teller (JT) effect in the magnesium phthalocyanine anion (MgPc-). The neutral MgPc has D-4h symmetry with a doubly degenerate e(g) affinity level and 14 B-1g plus 14 B-2g JT active modes. MgPc- is thus a physical realization of a e(g) circle times (B-1g circle plus B-2g) JT problem. We carried out a first principles DFT/LDA calculation of the electronic structure, full vibrational spectrum, and linear electron-vibration coupling constants for this system. From that we calculate a static JT energy gain of 50 meV - essentially due to a B-1g distortion - characterizing this as a relatively weak-coupling system. It is anticipated that quantum mechanical dynamic JT tunneling between the two equivalent B-1g distorted JT minima should be quite important. Two B-1g distorted saddle points are identified as the relevant transition states, with a barrier of 27 mcV above the minima. Previous work on this JT problem is also addressed. (c) 2007 Elsevier B.V. All rights reserved.
Jahn-Teller effect in the magnesium phthalocyanine anion
Tosatti E
2007
Abstract
We present an ab initio study of the static Jahn-Teller (JT) effect in the magnesium phthalocyanine anion (MgPc-). The neutral MgPc has D-4h symmetry with a doubly degenerate e(g) affinity level and 14 B-1g plus 14 B-2g JT active modes. MgPc- is thus a physical realization of a e(g) circle times (B-1g circle plus B-2g) JT problem. We carried out a first principles DFT/LDA calculation of the electronic structure, full vibrational spectrum, and linear electron-vibration coupling constants for this system. From that we calculate a static JT energy gain of 50 meV - essentially due to a B-1g distortion - characterizing this as a relatively weak-coupling system. It is anticipated that quantum mechanical dynamic JT tunneling between the two equivalent B-1g distorted JT minima should be quite important. Two B-1g distorted saddle points are identified as the relevant transition states, with a barrier of 27 mcV above the minima. Previous work on this JT problem is also addressed. (c) 2007 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
