Daniel P. Zaleski, Hansjochen Köckert, Susanna L. Stephens, Nick R. Walker

School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.

The Pure Rotational Spectrum of PbI from Broadband Rotational Spectroscopy

The Ohio State 69th International Symposium on Molecular Spectroscopy, June 19th, 2014.

Lisa-Maria Dickens and Corey Evans

Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.

Introduction

PbI has a 2П1/2 ground state

Radical diatomics in this state have garnered interest in the past

- SnCl- PbCl (RC07 2010 ISMS)

There has been spectroscopic in the past for PbI.

J. Mol. Spectrosc., 1993, 161, 552-559.

Chem. Phys. Lett., 1992, 190, 271-278.

J. Mol. Spectrosc., 2012, 280, 85-90.J. Mol. Spectrosc., 1998, 191, 108-116.

Chirped Pulse FTMW Spectroscopy

Broadband spectrometers with instantaneous frequency coverage from 2-8 GHz, 6.5-18.5 GHz, 18.5-26 GHz, and 25 – 40 GHz have been constructed.

Current Technology:AWG 24 Gs/s (12 GHz)Digital Oscilloscope 100 Gs/s (33 GHz)

600k FID’sCF3I, 6 bar Ar, Pb rod

Dynamic Range ~10,000:1

No Coils

200x

3 Primary Isotopes:

208Pb ~52%207Pb ~22%206Pb ~24%

207Pb spin 1/2

Exp. Theory*

B (MHz) 818.2834(3) 790.2489

D (kHz) 0.092(2)

A (THz) |239.034|

a (MHz) 186.85(5)

d (MHz) 239.76(1)

eQq (MHz) -701.42(5)

(p+2q) (MHz) 163.142(4)

(q) (MHz) -21.0(3)

* MP2/aug-cc-pVTZ-PP

Chem. Phys. Lett., 1992, 190, 271-278.

S/N ~50:1

Be = 819.3010(7) MHz

𝐵𝑒=18(15𝐵0−10𝐵1+3𝐵2)

αe = 2.0352(9) MHz

𝛼𝑒=2𝐵0−3𝐵1+𝐵2

𝑈 (𝑟 )=𝐷𝐸 ¿

ωe = 161.02(4) cm-1

Chem. Phys. Lett., 1992, 190, 271-278.

~241 kJ/mol

𝜔𝑒𝑥𝑒=𝐵𝑒(𝛼𝑒𝜔𝑒

6 𝐵𝑒2 +1)

2

ωeχe = 9690(12) MHz

DE = 20003(2178) cm-1

𝐷𝐸=𝜔𝑒2

4𝜔𝑒𝑥𝑒

300x

3 Primary Isotopes:

120Sn ~32%118Sn ~24%116Sn ~14%

Exp. Theory*

B (MHz) 1120.2711(4) 1126.6139

D (kHz) 0.1608(5)

A (THz) |72.19|

a (MHz) 224.71(7)

d (MHz) 99.96(3)

eQq (MHz) -697.6(2)

(p+2q) (MHz) -143.285(2)

* MP2/aug-cc-pVTZ-PP

S/N ~30:1

MC-SCF

Be = 1121.7667(9) MHz

αe = 2.991(9) MHz

γe = 0.9(5) kHz

𝑈 (𝑟 )=𝐷𝐸 ¿

ωe = 241.1(1) cm-1

ωeχe = 16740(16) MHz

DE = 25971(2823) cm-1

~311 kJ/mol

Trans. Farad. Soc.,1967, 64, 616-619.

Conclusions

Both PbI and SnI have a 2П1/2 ground state

Assigned a number of vibrational states for each of the Pb and Sn isotopes

Modeled the PES using Morse potential

ED are on the order of ~240 – 310 kJ/mol

Acknowledgments

Engineering and Physical Sciences Research Council

AWE (Aldermaston)

University of Bristol Colin Western