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The 67th International Symposium
on Molecular Spectroscopy, June 2012
Ruohan Zhang, Chengbing Qina and Timothy C. Steimle Dept. Chem. & BioChem., Arizona State University, Tempe, AZ,USA
Funded by: DoE-BES
The Optical Stark Spectrum of the [17.8]0+-X1+ Band of AuF
Thomas Varberg
Mccalaster College, St Paul, MN, USA
a Visitor from Dept. Chem. Phys. University of Science and Technology of China, Hefei, Anhui 230026, China
& Zeeman
“Noble” metals actually have a rich and an valuable chemistry
Noble metals
Review by Pyykkö
High speed of electrons near the nucleus mass increase
stabilization and contraction
The contraction of the 6s orbital unique chemical properties of Au.
Spectroscopic methods for probing electronic wavefunction:
a) Stark effect b) Zeeman effect c) Hyperfine interactions 197Au(I=3/2)
Previous Experimental Studies:
• Evans & Gerry JACS -2000 FTMW Bv, eQq(Au), CI (Au) & CI (F)
• Knurr, Butler & Varberg JPC-A 2009 [17.7]1-X1+ [17.7] mag. Hyp.
• Okabayashi et al CPL -2002 mm-wave Bv, eQq(Au), CI (Au) & CI (F)
Theoretical Studies (Very Numerous); Recent Ones :
• Andreev & BelBruno CPL -2000 Visible Emission =0&1X1+
• Butler….& Varberg JPC-A 2010 cw-dye laser [17.7]1,[14.0]1 & [17.8]0-X1+ sub-Doppler LIF; sputtering source
• Hill & Peterson JCTC 2012 Coupled Cluster prediction e, re, ect.
• Goll et al Phys. Rev. A 2007 DFT/Wavefunc hybrid el Ref #1
• Schwerdtfeger et al JCP 2011 Pseudopoteintials el Ref #2
• Fernández & Balbás PCCP 2011 vdW-DFe, re, ect. el Ref #3
Well collimatedmolecular beamRot.Temp.<10 K
Single freq. tunable laser radiation
PMT
Gated photon counter
Experimental set up for LIF studies
Helmholtz coils
Optical Zeeman Spectroscopy
Stark plates
Optical Stark spectroscopy
Metal target
Pulse valve
skimmer
Ablation laser
SF6
& Carrier
Au tube
Observations-Field-Free LIF
Varberg’s JCP 2010Pulsed dye laser; sputtering source; T 600KFWHM 3 GHz
P(1)
R(0)
Sub-Doppler I2
Sub-Doppler I2
Beam LIF AuF
Beam LIF AuF
Current studycw dye laser; sputtering source; T 10KFWHM 40 MHz
P(1) - Stark Effect
0 V/cm 3010V/cm
3010 V/cm 0 V/cm
X1
J=1
MJ=0
MJ=1
[17.8]0
J=0
MJ=0
Electric Field
Energ
yC
CB
B
Field Free
A
A
A
A
Laser Wavenumber17755.1217755.10
LIF
Sig
nal
Analysis of FF & Stark Spectrum of [17.8]0+-X1+
(case(a))SJ>Basis function:
HRot=BJ2 HStark=E∙ el
Field-Free SpectrumJCP 2010
T =17776.441cm-1; B”= 0.263409 cm-1 ; B’= 0.2532162cm-1
Stark Spectrum 88 representation ( J=0-7)
(X1+) = 4.148 (23) D
([17.8]+) = 2.201 (60) D
Discussion-StarkDipole moment (X1+) = 4.148 (23)
D9DNote: Au+1F-1
Goll et al 2007 ;DFT/wavefunc hybrid
Note: No predictions for [17.8]0+ state
DFT 3.60
CSSD(T) 4.46
CSSD(T)/DFT 4.42
Method Value (D)
CAM-DFT 4.24
“CAM” =Coulomb Attenuated
The “CAM-DFT” method does indeed give the best results for m predictions, as proposed in Ref. 1.
Discussion-StarkElec. Dipole moment (X1+) = 4.148 (23)
DRef. 2 Schwerdtfeger et al JCP 2011 Pseudopoteintials
“SC-SRPP-S” =Small Core; Scalar Relativistic; Pseudo- Potential -Stuttgart
“SC-NRPP-S” =Small Core; Non-Relativistic; Pseudo- Potential -Stuttgart
Relativity matters: 5.229 vs. 4.046 compared to experimental value of 4.148 D
Discussion-StarkDipole moment (X1+) = 4.148 (23)
D
Functional Value (D)
DRSLL 4.06
LMKLL 3.94
KBM 3.94
Non-local correlation van der Waals
PBE 3.96Generalized
Gradient Approximation
Ref. 3 ;Fernández & Balbás PCCP 2011 vdW-DFe, re, ect.
General Comment: All high-level predictions of (X1+) are good. Why?
1) Simple description of X1+: Au+(5d10)F-(3p6) single Slater determinant2) notstronglydependent on relativistic effects (only valence electrons)
Zeeman effectMotivation: Insight into [17.8]0+ state.
If [17.8]0+ = 1+ non-magnetic
If [17.8]0+ = 3Hund’s case (a) limit) non-magnetic
=0 & Eq. 1 non-magnetic
Eq. 1
Observations:
4500 G. “Perp.”
Field-freeP(1)Field-freeR(0)
4500 G. “Perp.”
non-magnetic magnetic
Analysis Zeeman Spectrum of [17.8]0+-X1+
All observed shifts due to the [17.8]0+ state.
Phenomenological model for shifts [17.8]0+ state: Ezee = B gJ BZ MJ
Results:
1 110 0.016
2 100 0.015
3 105 0.015
0 0 0.000
Non-zero gJ due to rotational mixing with
[17.7]1 state ?Detailed interpretation in
progress.
[17.8]0+ J gJE (MHz)
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