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Broadband Rotational Spectrum and Molecular Geometry of OCAgI
Nicholas R. Walker, Susanna L. Stephens, Anthony C. Legon
1
67th International Symposium on Molecular Spectroscopy, Ohio State University, 2012.
Engineering and Physical Sciences Research Council
Design of Laser Ablation Source for CP-FTMW Spectrometer
Design Challenges
Designs must consider; •Need for the target to rotate, translate and switch direction in a vacuum. •Geometry of source and location of laser. •Need for daily and weekly disassembly and maintenance. •Can we also have flexibility in selecting experimental conditions?
Laser ablation source informed by the designs currently used by Legon and co-workers, Duncan and co-workers, Gerry and co-workers, Ziurys and co-workers.
Laser ablation source
Rod holder
CP-FTMW Spectrometer
OCAuX (X=F,Cl,Br)
OCCuX (X=F,Cl,Br)
OCAgX (X=F,Cl,Br)
OCCuI
OCAuI
C.J. Evans, L.M. Reynard and M.C.L. Gerry, Inorg. Chem. 40, 6123 (2001)
N.R. Walker and M.C.L. Gerry, Inorg. Chem. 41, 1236 (2002)
N.R. Walker and M.C.L. Gerry, Inorg. Chem. 40, 6158 (2001)
N.R. Walker, S.G. Francis, S.L. Matthews, J.J. Rowlands and A.C. Legon, Mol. Phys. 105, 861 (2007)
S.G. Batten and A.C. Legon, Chem. Phys. Lett. 422, 192 (2006)
OCAgI• Transitions likely to be intense enough to
observe by CP-FTMW spectroscopy. • Why didn’t we find it when we searched in
2007 ????
Previous Studies of OCMX
OCAgI
8000 10000 12000 14000 16000 18000 Frequency/MHz
CF3I
107 AgI109 AgI
AgI
1% CO, 0.5% CF3I, 6 bar argon18000 averages (2 hours)
OCAgI
13200 13400 13600 13800 14000 14200 14400 Frequency / MHz
107AgI 109AgI
OCICF3
Exp.
Sim.
OC107AgI OC109AgI
Spectrum of OCICF3 characterised in Stephens et al. J. Chem. Phys. 135, 224309 (2011)
Table 1. OC107AgI OC109AgI O13C107AgI
0B / MHz 635.79578(11) 634.40135(10 628.723667(84)
DJ 102/ kHz 2.933(45) 2.986(41) 2.918(34)
(I)aa / MHz 769.84(22) 769.96(17) 769.98(14)
Na 41 35 44 r.m.s/kHz 5.0 3.9 3.5 O13C109AgI 18OC107AgI 18OC109AgI
0B / MHz 627.39303(17) 609.95682(19) 608.75801(34)
DJ 102/ kHz 2.868(68) 2.496(78) 2.69(13)
(I)aa / MHz 770.03(28) 769.74(37) 770.31(69)
Na 38 27 32 r.m.s/kHz 6.1 6.4 11.3 a Numbers in parentheses are one standard deviation in units of the last significant figure. N is the number of transitions included in the fit.
Results of Spectroscopic Fits
OCAgI r(CO) / Å r(AgC) / Å r(AgI) / Å
CCSD(T)/cc-pVTZ (re) 1.131 2.062 2.563
CCSD(T)/cc-pVQZ (re) 1.126 2.060 2.550
CCSD(T)(F12*)/cc-pVTZ (re) 1.125 2.057 2.541
CCSD(T)(F12*)/cc-pVQZ (re) 1.125 2.055 2.542
CCSD(T)(F12*)/cc-pVQZ +δECV (re) 1.123 2.036 2.526
Exp. (r0) 1.1234(8) 2.051(1) 2.5336(4)
Exp. ((1)
mr )a 1.12284(7) 2.05122(9) 2.5281(2)
Exp. (rs) 1.1236(5) 2.053(2) 2.530(2)b
Results of Structure Fitting
• Length of CO bond decreases on attachment to AgI. • r(AgI) also decreases slightly. • Basis set completeness is essential for accuracy in the theoretical
calculation.
r0 of free CO = 1.130 Å r0 of free AgI= 2.547 Å
13100 13150 13200 13250 13300 13350Frequency / MHz
v=0
v=0115InI
113InI
113In=95.7%115In=4.3%
Natural Abundances
Rotational Spectra of Indium Iodide Vibrationally-Excited States
v=1
v=2v=3
v =0
v =1
v = 2
J =8
76 }Rotational
Levels
J =8
76
13200 13400 13600 13800 14000
Frequency / MHz
v = 0
1234
8
1215
Rotational Spectra of Aluminium iodide Vibrationally-Excited States
27AlI J J= 1 2
[27Al is only naturally-abundant isotope of Al]
Acknowledgements
University of BristolSusanna StephensAnthony C. LegonWataru MizukamiDavid P. Tew
Financial Support
Engineering and Physical Sciences Research Council
PublicationS.L. Stephens, N.R. Walker and A.C. Legon, J. Chem. Phys., 136 064306 (2012)