Transcript mss 2006.ppt

Identification of the
[10.3] 4Φ7/2 – A 2Δ5/2 Transition
of Nickel Chloride
Leah C. O’Brien and Krystal Gibbs
Department of Chemistry
Southern Illinois University
Edwardsville, IL 62026
NiCl
• Ground state electronic configuration:
– Ni+(3d9)Cl-(3p6)
– Five low-lying electronic states
•
2P
3/2,
2P
1/2,
2D , 2D ,
5/2
3/2
and 2S+
• Excited states arise from:
– Low-lying Ni+(3d84s) configuration
– Covalent Ni(3d84s2)Cl(3p5)
– Covalent Ni(3d94s)Cl(3p5)
• Many states already identified through spectral
analysis
Experimental Method
• Used FT spectrometer associated with McMathPierce National Solar Observatory at Kitt Peak,
AZ, to record emission spectrum.
• NiCl molecules were produced in a King-type
carbon tube furnace loaded with NiCl2 and
heated to 1600 °C.
• The FT spectrometer was configured with a UV
quartz beamsplitter and silicon diode avalanche
detectors, to record the 8000-16000 cm-1 region.
Results
• Two new bands were observed in the 10,000 –
11,000 cm-1 region
– band heads at 10,168 and 10,561cm-1
• consistent with excited state vibrational frequency ~400 cm-1
– intensity ratio for the two systems is approximately 4:1
– we concluded that the 10,168 cm-1 system is the (0,0)
band and the 10,561 cm-1 system is the (1,0) band of
a new electronic transition
– 3 branches were identified in the 10,168 cm-1 band;
the 10,561 cm-1 band was too weak
-1
A portion of the 10168 cm band
10130
10140
10150
cm-1 10160
10170
Analysis
• Used method of combination differences to
confirm that the 10,168 cm-1 band connects to
the A 2∆5/2 state
• 1 P, 1 Q, and 1 R branch
• 10,166 cm-1 band assigned as the (0,0) band of
the [10.3] 4Φ7/2 – A 2Δ5/2 transition of NiCl
• Branches fit to polynomial expressions for the
excited and ground state
• Ground state parameters held fixed to values
from Hirao et al. (JMS 2000)
Molecular Parameters for the
4Φ
7/2 state of NiCl, v=0
Parameter
Value (cm-1)
T0
10327.3364
B0
0.168886783
D0
0.124168 x 10-6
H0
0.6261 x 10-13
q0
0.210 x 10-10
Electronic Structure of NiCl
• New theoretical studies of the electronic
structure of Ni halides
– Zou and Liu, JCP 124 (2006) 154312
• Compare predicted states with known
states
16000
cm-1
Ni+
NiCl
2F
5/2
2F
7/2
2D
2F
2P
2S-
12000 cm-1
NiCl
2D
3/2
2D
5/2
2P
3/2
2D
5/2
2P
1/2
2P
3/2
2P
3/2
2S+
2S-
72% 2S- + 27% 2P1/2
3/2
4F
4F3/2
5/2
4F
7/2
8000 cm-1
NiCl
4F
9/2
4F
4D
4P
4S-
5/2
7/2
1/2, 9/2
1/2, 3/2
3/2, 1/2, 5/2
7/2
3/2, 5/2
1/2
4F
7/2
4P
3/2
45% 4D3/2 + 44% 4P3/2
4000 cm-1
79% 2S+ + 21% 2P1/2
2D
3/2
2S+
2D
0 cm-1
2D
5/2
2P
Zou and Liu,
no spin-orbit
2S+
2D
3/2
2S+
2D
3/2
2P
1/2 2
2P
D5/2
3/2
2P
Zou and Liu,
with spin-orbit
2P
Experimental
1/2 2
D5/2
3/2
Summary
• [10.3] 4Φ7/2 – A 2Δ5/2 transition identified and
analyzed
• Calculations with spin-orbit interaction clarify
electronic structure, point out discrepancies, and
confirm assignments
– [12.3] 2S+ should be [12.3] 2S– States in 8000 – 10000 cm-1 region are very mixed;
use Hund’s case (c)
• Many states still not observed in the nearinfrared and visible regions
New state added to picture of NiCl
Acknowledgements
• NSF Division of Chemistry; RUI Funding
• ACS-PRF; Type B Funding
• Mike Dulick, National Solar Observatory