ROTATIONAL AND RENNER-TELLER ANALYSES OF THE GROUND AND EXCITED STATE LEVELS

OF THE JET-COOLED CS2 ION

Dennis J. Clouthier & Sheng-Gui HeDepartment of ChemistryUniversity of Kentucky

Lexington, KY 40506-0055

 

 Pulsed Discharge Jet Apparatus

Precursor & Argon

Discharge Jet Spectroscopy

Molecules:

SiH2, SiF2, SiCl2, HSiF, HSiCl, HSiBr, HSiI, H2C=Si

GeH2, GeF2, GeCl2, HGeCl, HGeBr, HGeI, H2C=Ge

Free Radicals:

SiCH, SiCCl, GeCH, Ge2, FS2, HPCl, HPBr, BS2

BF2, BCl2, HBF, HBCl, HBBr, HCCS, HCCSe

Ions:

???

Discharge Circuit

*

+

ˉ

Jet-Cooled Ions Detected by LIF

Cations

CO2+, N2O+, C6F6

+, HCP+, CS2+

Anions

SCCSˉ

S2ˉ ?

M. Nakajima, Y. Yoneda, Y. Sumiyoshi, T. Nagata, and Y. Endo, J. Chem. Phys. 119, 7805 (2003)

CS2+ History

Low resolution emission spectra (Barrow, 1950)

B-X high resolution emission spectra (Callomon, 1958)

A-X medium resolution emission spectra (Balfour, 1976)

Matrix studies of LIF and emission spectra (Bondybey, 1980)

Photoelectron spectra of X and A state vibronic levels (Ng, 1997, 2001)

No LIF or emission spectra of jet-cooled CS2+ or Renner-

Teller fit.

~

~

~ ~

~

~

LIF Spectrum of CS2+

Fermi Resonance in the CS2+ LIF

Spectrum

Br

High-Resolution LIF Spectrum

CS2+ MO’s and

Structures

2u2g

…(2u)4 (2g)3 X 2g

~…(2u)3 (2g)4 A 2u

~

r" = 1.5554(10) r' = 1.6172(12)

CS2+ Emission

Spectra

Major Fitted Constants

Parameter

X A

ExperimentAb

InitioExperiment

Ab Initio

1 655.0(12) --- 582.00(47) 576.8

2 355.41(67) 345.4 303.07(44) 297.0

-0.1719(24) -0.1782 0.1221(57) 0.251

A -467.00(48) -446 -177.0(97) -173.6

W1 18.778(76) 15.803(39) ---

W2 1.07(31) --- ---

rms 1.62 0.56

~~

Comparison of CS2+ and

BS2

Parameter

X A

CS2+ BS2 CS2

+ BS2

1 655.0(12) 544.58 582.00(47) 512.71

2 355.41(67) 284.00 303.07(44) 309.49

-0.1719(24) -0.2119 0.1221(57) 0.0143

A -467.00(48) -414.43 -177.0(97) -259.47

W1 18.778(76) 19.213 15.803(39) 14.119

W2 1.07(31) 0.950 --- ---

rms 1.62 2.15 0.56 0.49

~~

Ground State Energy Levels

Excited State Energy Levels

PFI-PE Spectra

J. Liu et al., J. Phys. Chem. A, 105, 2183 (2001) measured extensive PFI-PE spectra of CS2 CS2

+ (A 2u) at ±4 cm-1 resolution.

Spectra assigned based on ab initio potential.

We have reanalyzed spectrum using our assignments.

Fit 45 energy levels to rms of 2.17 cm-1.

Derived constants in good agreement with more precise LIF constants.

~

Ground and excited state molecular structures.

Renner-Teller analysis for both states.

Spin-orbit splittings accurately determined.

Fermi resonances treated quantitatively in both states.

PFI-PE data fitted.