Susanna Stephens

H2OAgF characterised by Rotational Spectroscopy

Objectives• Systematic investigation B MX species where B is a Lewis ∙∙∙

base, M a coinage metal and X a halogen.

• Compare H2O AgF and H∙∙∙ 2O HF ∙∙∙

with

H2O AgCl and H∙∙∙ 2O HCl∙∙∙

• Trends with previous work

• OC-MX and Ar-MX studies by Gerry and co-workers.

• H2S MX and H∙∙∙ 2O MX by Walker, Legon and co-∙∙∙

workers

Balle-Flygare spectrometer

To vacuum

Stationary Mirror

Adjustable mirror

Fabry-Perot cavity containing standing wave and expansion of supersonic jet

Adiabatic expansion of SF6 / H2O / Ar

Solenoid valve

Gas line

Silver rod and rotator

532 nm Nd:YAG laser

Focusing lens

To microwave circuits

Rod rotator

Laser arm

Gas line attached to solenoid valve

Microwave emission antenna

Laser ablation nozzle

A.C. Legon, in: G. Scoles (Ed.), Atomic and Molecular Beam Methods, vol. 2, Oxford University Press, Oxford, 1992 (Chapter 9)S. G. Batten, A. G. Ward, A. C. Legon, J. Mol. Struct., 300, 780, (2006)

Predicted structure

First observed with H2O···HFZ. Kisiel, A.C. Legon, D.J. Millen, Proc. R. Soc. Lond. A 381, 419, (1982)

Ag FO

rAgO rAgF

a

Analogous systemH2O···AgCl and H2S···AgCl

H2O···CuCl and H2S···CuCl studied subsequently are analogous

H2O···AgCl and H2S···AgCl S. J. Harris et al., Ang.Chem.Int.Ed., 49, 181 (2010)H2O···AgCl and H2O···CuCl V. A. Mikhailov et al., J. Chem. Phys., 134, 134305 (2011)H2S···CuCl and H2S···CuCl N. R. Walker et al., J. Chem. Phys., Accepted

12273.35 12273.45 12273.55 12273.65Frequency MHz

Molecular transitions

• CCSD(T) structure prediction• Comparison B···MX• 300 MHz search range

H216O109AgF

H216O107AgF

12294.4 12294.5 12294.6 12294.7Frequency MHz

H216O109AgF

H216O107AgF

J’’-J’ = 101←202 J’’-J’ = 111←212

• J’’-J’ = 101←202

• J’’-J’ = 202←303

• J’’-J’ = 111←212 , 111←210, 212←313 , 212←311

H216O107AgF H2

16O109AgF H218O107AgF H2

18O109AgF

B0 + C0 /MHz 6147.3147(15) 6147.3279(26) 5821.3536* 5821.2285*

B0 - C0 /MHz 20.8253(10) 20.8240(17) 18.6255 18.6248J / kHz 1.266(44) 1.241(75) 1.220 1.077JK/ kHz 74.31(43) 74.70(73) 73.03 73.30

N 6 6 4 4r.m.s/kHz 2.5 4.3 - -

D216O107AgF D2

16O109AgF HD16O107AgF HD16O109AgFB0 + C0 / MHz 5661.9184* 5661.7632* 5891.1518* 5891.0947*

J / kHz 1.359 1.391 1.115 1.262N 2 2 2 2

r.m.s/kHz - - - -

*Statistical uncertainties cannot be determined where four parameters are derived from 4 measurements or two parameters derived from two measurements

Spectral Constants

Spectral fitting carried out in PGOPHER

Barrier to inversion

Ag FO

rAgO rAgF

a

ab initioCCSD(T)/VQZ

re

Experimental

r0

Ag-F 1.962 1.985(11)Ag-O 2.182 2.168(11)

ϕ 46.09 42(1)σr.m.s. - 0.107

As A0 is not determined and the hydrogens lye off the a-axis geometry of the water subunit assumed to be equal to that of free water

Geometry

ϕ / k /N m-1

H2O···F2 49(2) 3.63(7)

H2O···Cl2 43 (3) 8.0(1)

H2O···HF 45.5 24.9

H2O···HCl 34.7(4) 12.9

H2O···ClF 59(2) 14.16(4)

Bonding in H2O···YX complexesWhere Y is a coinage metal or a halogen

rH2O-Y /Å rY-X /Å rY-X /ÅFor Free MX

ϕ / k /N m-1

H216O···107AgF 2.168(15) 1.985(11) 1.9868 42(1) 57(2)

H216O···107Ag35Cl 2.198(10) 2.273(6) 2.281 37(2) 37

H216O···63Cu35Cl 1.91 (10) 2.062(6) 2.0541 40(1) 58(2)

• H2O···ClF H2O··F2 S.Cooke et al. J. Chem. Eur., 11, 7 (2001)• H2O ···Cl2 J.B.Davey et al., J. Chem. Phys. 114, 6190 (2001)• H2O···HCl Z. Kisiel et al., J. Chem. Phys., 104, 6970 (2000)• H2O···HF Z. Kisiel, A.C. Legon, D.J. Millen,

Proc. R. Soc. Lond. A 381, 419, (1982)

• AgF Okabayashi et al., J. Mol. Spectr., 209, 66 (2001)• H2O···AgCl and H2O···CuCl

V. A. Mikhailov et al., J. Chem. Phys., 134, 134305 (2011)

Acknowledgements

<http://pgopher.chm.bris.ac.uk/>

University of BristolNick WalkerTony C. LegonDavid TewColin M. Western

For development and adaption of PGOPHER for rotational spectroscopy

F Cl

ϕ / k /N m-1 ϕ / k /N m-1

H2O···HX 45.5 24.9 34.7(4) 12.9

H2O···AgX 42(1) 57(2) 37(2) 37

Frequency MHz

H218O107AgF H2

18O109AgF D216O107AgF D2

16O109AgF2 1 2 → 1 1 1 - - - -2 0 2 → 1 0 1 11642.6650b 11642.4216 11323.7934b 11323.48212 1 1 → 1 10 - - - -3 13 →212 17435.5519a 17435.1916 - -3 03 →202 17463.9254a 17463.5656 16985.6085b 16985.13973 12 →211 17491.4314b 17491.0659 - -

Frequency MHz

H216O107AgF H2

16O109AgF HD16O107AgF HD16O109AgF

2 1 2 → 1 1 1 12273.4679b 12273.4975 - -2 0 2 → 1 0 1 12294.5880b 12294.6134 11782.2656b 11782.14902 1 1 → 1 10 12315.1178a 12315.1389 - -3 13 →212 18410.1225b 18410.1622 - -3 03 →202 18441.8057b 18441.8465 17673.3226b 17673.14783 12 →211 18472.5998b 18472.6385 - -

a Measurement with isotopically enriched 107Ag rodb Measurement with natural abundance silver rod. Also observed with isotopically enriched. Less intense signal due to inconsistent 107Ag layer over glass rod at later times of experiment

H2O···AgF molecular transitions

Experimental M-L M-XrML (Cl)

/rML (F)

OCAgCl 2.016 2.2551.026

OCAgF 1.965 1.944ArAgCl 2.597 2.285

1.015ArAgF 2.558 1.986KrAgCl 2.646 2.277

1.017KrAgF 2.601 1.983

XeAgCl 2.711 2.2711.018

XeAgF 2.663 1.98H2O-AgCl 2.198 2.272

A0 GHz B0 GHz C0 GHz SearchMHzTheoretical

H2O-AgF 2.1424 1.98 1.026 357.0182 3.1249 3.1069 12463.62.16499 1.015 357.043 3.0902 3.0726 12325.62.16062 1.017 357.0387 3.0962 3.0785 12349.42.15908 1.018 357.0366 3.0992 3.0815 12361.4

2.168(11) 1.985(11) Exp: 12294.0

• Ratio of AgCl:AgF bond lengths• This has a fairly small range across all ligands• Find Ag-F distance across this range

Structure prediction by comparison

If I1and I2 are the nuclear spin vectors of the H2O protons , the Pauli exclusion principle requires that, of the allowed spin states, I1 + I2 = 0 must occur in combination with K-1 = 0 rotational levels while the state | I1 + I2 |= 1 must occur in combination with k-1 = 1 rotational levels . Hence, no spin-spin interactions involving H2O protons can contribute to the extra structure observed in the 202 – 101 and 303 – 202 transitions.

OrI = 1 state cannot be combined with a wavefunction with K-1=0 but can with K-1=1 state.I = 0 can only appear in a K-1=0 state.

H

O

H

Ag F

I = I1 + I2 = 1(triplet)

H

O

H

Ag F

I = I1 + I2 = 0(Singlet)