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ELECTRONIC STRUCTURE AND SPECTROSCOPY OF THE MGO2 CATION
O. YAZIDI, A. BEN HOURIA AND Z. BEN LAKHDAR, LSAMA, Universitè de Tunis El Manar, Tunis, TUNISIA
M. L. SENENT, Departamento de Astrofísica Molecular e Infrarroja, Instituto de Estructura de la Materia, C.S.I.C., Serrano 121, Madrid 28006, SPAIN
M. HOCHLAF, Université Paris-Est, Laboratoire de Modélisation et Simulation Multi Echelle, MSME FRE 3160 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallée, FRANCE
Chemical Physics, 215, 348 (2008)
MgO2+
Relevance for earth AtmospherePossible intermediate or product of reactions Type O3 + M+
Outline
StructureElectronic statesPhotodissociation of MgO2
+
MgO2+ → MgO+ + O (3P)
MgO2+ → Mg+ + O2 (X3Sg
-)MgO2
+ → Mg+ + O2 (1Dg)
Spectroscopic parameters from 3D-PES
MgO2+ minumum energy structures
Mg
O O
OMg O X4 S-
X2A2
DE = 0.77 eV
MRCI/CASSCF/cc-pV5ZActive space: 2s(O), 2p(O), 3s(Mg), 3p(MG)
2.4104 1.2102
42.6º
1.8913
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Ene
rgy
/eV
76543 RMgO /bohr
RMgO
Mg O O2.28
X 4
12
12
12
Mg+ ( 2Sg ) + O2( X 3g- )
Mg+ ( 2Sg ) + O2( a 1g)
Mg+ ( 2Sg ) + O2( b 1g+ )
R(MgO) /Bohr(ROO = 2.28)
l-MgOO+
X4 S-
CASSCF
8
6
4
2
0
Ene
rgy
/eV
10864 ROO /bohr
Mg O O4.55
+X4
12
12
12
12
22
14
24
24
22
12
22
14
14
MgO+ (X2 ) + O(3Pg)
MgO+ (2 ) + O(3Pg)
(A)
R(OO)/Bohr RMgO = 4.55 bohr
l-MgOO+
X4 S-
MRCI/CASSCF
4
3
2
1
0
Ene
rgy
/eV
180160140120100806040/degree
+Mg
O O4.55
2.28
1 2A"
2 2A"
3 2A"
1 2A'
2 2A'
3 2A'
1 4A"
X 4
1 2
1 2
1 2
(A)
bending angle
l-MgOO+
X4 S-
CASSCF
7
6
5
4
Ene
rgy
/eV
10864 RMgO /bohr
Mg
OO
3.56 RMgO42°
+
X 2A" 1 2A'
2 2A"
1 4A"
2 2A'
3 2A"
3 2A'
2 4A"
1 4A'
2 4A'
3 4A' 4 2A"
4 4A"
5 4A"
5 2A''
3 2A'
3 4A'
MgO+ ( X 2 ) + O( 3Pg )
MgO+ ( 2+ ) + O( 3Pg )
(A) MgO2+( 2A2)
CASSCFR(MgO)/Bohr RMgO = 3.56 bohr
6
4
2
0
Ene
rgy
/eV
1210864 R /bohr
Mg
O O
R
2.60
+z
y
X 2A2
1 2B2
22B2
1 2B1
2 2B1
3 2B1
1 2A1
2 2A1
2 2A2
1 4A2
1 4A1
(A)
Mg+ ( 2Sg ) + O2( X 3g- )
Mg+ ( 2Sg ) + O2( a 1g )
Mg+ ( 2Sg ) + O2( b 1g+ )
FC
1 4B1
14B2
MgO2+( 2A2)
MRCI/CASSCF
3D-PES
MRCI/CASSCF/cc-pV5Z l-MgOO (X4 S-) 22 geometries up to energies 700 cm-1 (along the MgO
st) up to energies 5000 cm-1 (along the OO st) Bend OMgO (X2A2 ) 35 geometries Up to energies 4000 cm-1
MgO2+( 2A2) l-MgOO+( 4S-)
ROO2.287
RMgO3.57 4.555
θe42.6 180
G01343.6 831.3
Ae1.113
Be0.393 0.1238
Ce0.292
a1A
0.001555
a2A
0.014606
a3A
-0.007097
a1B
0.003458 0.000523
a2B
-0.000995 -0.00171
a3B
0.002180 0.00398
a1C
0.001588
a2C
0.000357
a3C
0.002879
X~X~A
1 A2 A3 B1 B2 B3 C1 C2 C3
w1 667.7
660.8
1588.0
w2 1078.0
1071.8
46.1
w3 488.8
668.8
117.8
n1 641 1427.1
n2 1837 48.1
n3 511 126.8
MRCI Spectroscopic parameters
CASSCF (sta.met.MOLPRO)
X~X~A
1 A2 A3 B1 B2 B3 C1 C2 C3
(v1,v2,v3) Energy
(0,0,0) 0
(0,0,1) 511
(1,0,0) 641
(1,0,1) 1008
(0,0,2) 1158
(2,0,0) 1259
(1,0,2) 1494
(0,0,3) 1660
(3,0,0) 1784
(0,1,0) 1837
(2,0,1) 1882
(2,0,2) 1968
Variationally computed vibrational levels of MgO2+ ( 2A2). T
he energies are in cm-1.
accuracy 10 cm-1
Variationally computed vibrational levels of MgOO+ ( 4S-). The energies are in cm-1.
J=0 J=1
(v1,v2,v3) Energ
y
(v1,v2,v3) Energy (v1,v2,v3) Energy (v1,v2,v3) Energy
(0,0,0) 0 (0,6,1) 478 (0,1,0) 48 (0,3,3) 535
(0,2,0) 96 (0,10,0) 501 (0,3,0) 146 (0,9,1) 555
(0,0,1) 126 (0,0,4) 512 (0,1,1) 179 (0,1,4) 573
(0,4,0) 194 (0,2,3) 536 (0,5,0) 245 (0,11,0) 601
(0,2,1)) 229 (0,6,2) 546 (0,3,1) 282 (0,5,2) 606
(0,0,2) 256 (0,8,1) 590 (0,1,2) 314 (0,3,4) 647
(0,6,0) 295 (0,10,1) 607 (0,7,0) 347 (0,11,1) 661
(0,2,2) 333 (0,2,4) 630 (0,3,2) 387 (0,1,5) 690
(0,4,1) 367 (0,12,0) 654 (0,1,3) 424 (0,13,0) 710
(0,0,3) 392 (0,0,5) 663 (0,7,1) 450
(0,8,0) 397 (0,4,3) 689 (0,5,1) 456
(0,4,2) 439 (0,8,2) 703 (0,9,0) 493
In this work:
The atmospherically relevant MgO2+ species has been characterized.
From the Potential Energy Surfaces for various electronic states, we suggest severalphotodissociation channels.
The spectroscopic parameters of the two stable forms are determined variationnally from 3D-PES.
Summary