[He]2s2. [Ne]3s2. [Ar]4s2. [Rn]7s2. MOM? EXPECT M2+O2-. SO WHY WOULD. IT BOND TO M? Page 4 ... for high precision spectral measurements aimed at.
An ab initio study of the alkaline earth oxides BeOBe, MgOMg, CaOCa, SrOSr, BaOBa and RaORa. Bojana Ostojić (Belgrade), Per Jensen (Wuppertal), Peter Schwerdtfeger (Massey University, New Zealand), Phil Bunker (NRC, Ottawa).
An ab initio study of the alkaline earth oxides BeOBe, MgOMg, CaOCa, SrOSr, BaOBa and RaORa. Bojana Ostojić (Belgrade), Per Jensen (Wuppertal), Peter Schwerdtfeger (Massey University, New Zealand), Phil Bunker (NRC, Ottawa). “Hypermetallic” since have one more metal atom than they should
[He]2s2
[Ne]3s2
[Rn]7s2
[Ar]4s2
EXPECT M2+O2-. SO WHY WOULD IT BOND TO M?
MOM?
[He]2s2
[Ne]3s2
[Rn]7s2
[Ar]4s2
EXPECT M2+O2-. SO WHY WOULD IT BOND TO M? BECAUSE MO IS CLOSER TO M+O-
MOM?
[He]2s2
[Ne]3s2
[Rn]7s2
[Ar]4s2
EXPECT M2+O2-. SO WHY WOULD IT BOND TO M? BECAUSE MO IS CLOSER TO M+O-
MOM OK!
[He]2s2
[Ne]3s2
So these M2O mols are M+O2-M+
[Ar]4s2
MOM OK!
Apart from BeOBe, little known experimentally. Our interest is three-fold: To make precise ab initio calculations on them in order to understand the electronic structure, To predict the IR and electronic spectra and to compare with the experimental spectra,
To calculate Singlet-Triplet splittings and S-T interaction strengths in order to test these molecules as candidates for high precision spectral measurements aimed at looking for a time-variation in Mp /me.
BeOBe, MgOMg, CaOCa, SrOSr, BaOBa and RaORa.
We find that all these MOM molecules have A linear 1Σg+ ground electronic state and a fairly low lying linear 3Σu+ first excited electronic state. S-T spin-orbit coupling too small for them to be good candidates for use in measuring the time dependence of the fundamental parameters
BeOBe bending PE curves
Be
O
ρ
Be
~ Te(a) = 293 cm-1
Singlet-triplet splitting
exp
113
1039
1414 Merritt, Bondybey and Heaven, JPC A113, 13300 (2009)
Singlet IR spectrum
At 300 K
Triplet IR spectrum
BOTH ARE VERY WEAK
Te(a) = 671 cm-1
Diatomic 24Mg16O 774.7 cm-1
3.7 D
420 nm
MgOMg 310 nm
360 nm 340 nm
4.0 D
4.1 D 2.9 D
From Discussion:
~ A1Σu+ - X 420 nm ~ E1Πu - X 310 nm
~3 - a b Πg 360 nm ~3 c Πg - a 340 nm
15
CaOCa Also think that spectrum shows linear CaCaO molecule
Ca O
linear 40Ca+16O
Ca
CaCaO 3
CaO
486.8, 476
542.5 44Ca+16O
1200 bent
3
477, 468
O3 44Ca+55% 18O
533.5
3 526.5
44Ca+55% 18O
In solid N2 at 17 K
2
|
720
40Ca16O
υ = 722.4 cm-1 in gas phase υ = 707 cm-1 in N2 matrix.
Our results for CaOCa 1 + 472, 461 in the X Σg state: 40-16-40 44-16-44 40-18-40 44-18-44
υ1 345 330 344 329
υ2 55 55 52 52
υ3 755 749 719 713
SrOSr singlet-triplet interaction
S-T interaction?
ΔE ~ 2 cm-1 What is S-T matrix element?
even J/odd J
even N/odd N
SrOSr
ST matrix element = = -0.01 cm-1
~ 00 a ~ X 71
ΔE ~ 2 cm-1 Thus energy shift ~ (0.01)2/2 cm-1 = 0.00005 cm-1
MOM equi bond length S-T splitting
20
BaOBa bending PE curves Ba0.5+ O- Ba0.5+
730 nm
910 nm
Predicted emission wavelengths
Gee et al.
The cluster isolated chemical reaction technique.
BaOBa West and Poland JCP 66, 2139 (1977)
Triplet Emission ~700 nm
Singlet Emission ~900 nm
