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)