1 3
Theor Chem Acc (2015) 134:128
DOI 10.1007/s00214-015-1745-0
REGULAR ARTICLE
Photodissociation dynamics of the D
+
2 ion initiated by several
different laser pulses
Gábor J. Halász
1 · András Csehi
2 · Ágnes Vibók
2,3
Received: 13 June 2015 / Accepted: 5 October 2015 / Published online: 14 October 2015
© Springer-Verlag Berlin Heidelberg 2015
LICI on the dissociation dynamics of the D
+
2 molecule
strongly depend upon the laser parameters applied.
Keywords Photodissociation · Nonadiabatic effect ·
Laser-induced conical intersection · Diatomic molecule ·
Pulse length
1 Introduction
By separating the motion of the fast-moving electrons
and the slow nuclei in a molecular system the Born–
Oppenheimer (BO) approximation [ 1 ] usually can treat
the dynamical process in a molecule after absorbing a
photon. In this picture the nuclei move over a potential
energy surface (PES) obtained from the electronic (adiabatic) eigenstates and therefore electrons and nuclei do
not easily exchange energy. Although several chemical
and physical dynamical processes can be described on
a single Born – Oppenheimer PES, yet, in many important cases like radiationless relaxation of excited electronic states, dissociation, proton transfer or isomerization processes of polyatomic molecules etc. this
approximation breaks down. The nuclear and electronic
motion then couple and so-called conical intersection
(CI) arises [ 2 – 11 ]. In this situation the energy exchange
between the electrons and nuclei can become important.
It is widely recognized today these conical intersections
are very important in the nonadiabatic processes which
are ubiquitous in photophysics and photochemistry.
For diatomic systems that have only one degree of freedom, it is not possible for two electronic states of the same
symmetry to become degenerate and as a consequence of the
well-known noncrossing rule an avoided crossing results.
However, it stands only in fi eld-free space. It was pointed out
Abstract Nonadiabatic effects are ubiquitous in physics and chemistry. They are associated with conical intersections (CIs) which are degeneracies between electronic
states of polyatomic molecules. Recently, it has been recognized that so-called light-induced conical intersections
(LICIs) can be formed both by standing or by running
laser waves even in diatomics. Owing to the strong nonadiabatic couplings, the appearance of such laser-induced
conical intersections (LICIs) may signifi cantly change the
dynamical properties of a molecular system. In the present
paper we investigate the photodissociation dynamics of D
+
2
ion initiating the nuclear dynamics from the superposition
of all the vibrational states produced by ionizing D 2 . The
kinetic energy release and the angular distribution of the
photodissociation products are computed with and without
LICI for the several different values of the laser parameters.
We performed both one- and two-dimensional calculations,
as well. In the fi rst scheme the molecules were rotationally
frozen, whereas in the latter one, the molecular rotation is
included as a full additional dynamic variable. The results
obtained undoubtedly demonstrate that the impact of the
Published as part of the special collection of articles “Festschrift
in honour of P. R. Surjan”.
* Ágnes Vibók
vibok@phys.unideb.hu
1
Department of Information Technology , University
of Debrecen , PO Box 12 , 4010 Debrecen , Hungary
2
Department of Theoretical Physics , University of Debrecen ,
PO Box 5 , 4010 Debrecen , Hungary
3
ELI-ALPS, ELI-HU Non-Profi t Ltd , Dugonics tér 13 ,
6720 Szeged , Hungary
165
Reprinted from the journal
Theor Chem Acc (2015) 134:128
DOI 10.1007/s00214-015-1745-0
REGULAR ARTICLE
Photodissociation dynamics of the D
+
2 ion initiated by several
different laser pulses
Gábor J. Halász
1 · András Csehi
2 · Ágnes Vibók
2,3
Received: 13 June 2015 / Accepted: 5 October 2015 / Published online: 14 October 2015
© Springer-Verlag Berlin Heidelberg 2015
LICI on the dissociation dynamics of the D
+
2 molecule
strongly depend upon the laser parameters applied.
Keywords Photodissociation · Nonadiabatic effect ·
Laser-induced conical intersection · Diatomic molecule ·
Pulse length
1 Introduction
By separating the motion of the fast-moving electrons
and the slow nuclei in a molecular system the Born–
Oppenheimer (BO) approximation [ 1 ] usually can treat
the dynamical process in a molecule after absorbing a
photon. In this picture the nuclei move over a potential
energy surface (PES) obtained from the electronic (adiabatic) eigenstates and therefore electrons and nuclei do
not easily exchange energy. Although several chemical
and physical dynamical processes can be described on
a single Born – Oppenheimer PES, yet, in many important cases like radiationless relaxation of excited electronic states, dissociation, proton transfer or isomerization processes of polyatomic molecules etc. this
approximation breaks down. The nuclear and electronic
motion then couple and so-called conical intersection
(CI) arises [ 2 – 11 ]. In this situation the energy exchange
between the electrons and nuclei can become important.
It is widely recognized today these conical intersections
are very important in the nonadiabatic processes which
are ubiquitous in photophysics and photochemistry.
For diatomic systems that have only one degree of freedom, it is not possible for two electronic states of the same
symmetry to become degenerate and as a consequence of the
well-known noncrossing rule an avoided crossing results.
However, it stands only in fi eld-free space. It was pointed out
Abstract Nonadiabatic effects are ubiquitous in physics and chemistry. They are associated with conical intersections (CIs) which are degeneracies between electronic
states of polyatomic molecules. Recently, it has been recognized that so-called light-induced conical intersections
(LICIs) can be formed both by standing or by running
laser waves even in diatomics. Owing to the strong nonadiabatic couplings, the appearance of such laser-induced
conical intersections (LICIs) may signifi cantly change the
dynamical properties of a molecular system. In the present
paper we investigate the photodissociation dynamics of D
+
2
ion initiating the nuclear dynamics from the superposition
of all the vibrational states produced by ionizing D 2 . The
kinetic energy release and the angular distribution of the
photodissociation products are computed with and without
LICI for the several different values of the laser parameters.
We performed both one- and two-dimensional calculations,
as well. In the fi rst scheme the molecules were rotationally
frozen, whereas in the latter one, the molecular rotation is
included as a full additional dynamic variable. The results
obtained undoubtedly demonstrate that the impact of the
Published as part of the special collection of articles “Festschrift
in honour of P. R. Surjan”.
* Ágnes Vibók
vibok@phys.unideb.hu
1
Department of Information Technology , University
of Debrecen , PO Box 12 , 4010 Debrecen , Hungary
2
Department of Theoretical Physics , University of Debrecen ,
PO Box 5 , 4010 Debrecen , Hungary
3
ELI-ALPS, ELI-HU Non-Profi t Ltd , Dugonics tér 13 ,
6720 Szeged , Hungary
165
Reprinted from the journal