Transcript Gordon_CoH.ppt

Fourier Transform Emission
Spectroscopy of CoH and CoD
Iouli E. Gordon
Robert J. LeRoy
Peter F. Bernath
Departments of Physics
and Chemistry
Previous work
A 3Φ3
A 3Φ4
A. Heimer, Z. Phys. 104, 448(1937)
Measured (0,0) and (1,0) bands at
449.2 and 420.3 nm
~12400 cm-1
~22000 cm-1
A′ 3Φ3
A′ 3Φ4
Klynning et al., Phys. Scr. 6, 61(1972), 7, 72(1973), 24, 21(1981)
Ram
Varberg
Barnes
et al.,
et
etJ.
al.,
al.,
Mol.
J.J.Mol.
Mol.
Spectrosc.
Spectrosc.
Spectrosc.
175,173,
138,
1 100
630 (1989)
Recorded
and
rotationally
analyzed:
Recorded
Recorded
Fourier
several
sub-Doppler
bands
3 spectra
byemission
laser
of excitation
CoH and CoD
CoD:
A 3Φtransform
4─ X Φ4: (0,0), (1,1), (1,0), (2,1), (0,1) and (1,2)
3Φ -of
3Φ transition
3Φ
spectra
spectroscopy
A’
and
3Φ observed
(0,1)
using
3Φbands
resolved
laser
of(1,0)
A′
excitation
fluorescence
from
4 X (0,0)
4 Aand
4─
X
:
(0,0),
3
3
3Φ excited
3Φ - enabled
Xspectroscopy.
an
Ω=3
Studied
3Φ
spin
(0,0)
component,
hypefine
3band
of structure
A′(1,1),
which
in (0,0) to find
4 transition
3 (1,0)
CoH:
Aand
─
X
Φ
:
(0,0),
4
4
Xband
a3Φnew
and
electronic
lower
3Φ
resolution
state
CoH.
~2470
3Φ :spectra
cm-1(0,1)
above
of transitions
X3Φ4 as well
3 transition
Afor
─
X
(0,0),
3
3
as to (5,0)
from
determine
to (0,0)
spin-orbit
for both splitting
molecules.
between
Extended
Ω”=4 and 3
components
(728(±3)
cm-1were
)
Varberg’s
resolved
fluorescence
results
to CoD.
Ω=±1
transitions
not
observed
in these works
3
3
X3Φ3
X3Φ4
Previous work
Freindorf et al.,
J. Chem. Phys. 99, 1215
(1993)
Motivation for this work
• So far only transitions involving Ω=4 and Ω=3
components of the ground state have been observed
(Ω=2 is missing)
• Ω=±1 transitions were not observed at high resolution
in previous works
• Only one parity component was assigned in the X 3Φ3
state
• There is not sufficient data for Dunham and combined
isotopologue fits of CoH and CoD
• Search for the new electronic transitions
King Furnace
To pump
Water jacket
Heating element
H2+ Ar(He)
Insulation (carbon felt)
H2+ Ar(He)
Co metal
Experimental details
Region:
Beamsplitter:
Lens and windows:
Optical filter:
Detector:
Resolution:
Number of scans:
15500-8500 cm-1
Quartz
BaF2
650 nm red pass
Si:diode
0.05 cm-1
~200
Region:
Beamsplitter:
Lens and windows:
Optical filter:
Detector:
Resolution:
Number of scans:
9500-5000 cm-1
CaF2
BaF2
2900 cm-1 blue pass
InSb
0.04 cm-1
~200
Part of the CoD spectrum A′ 3Φ-X 3Φ
V=-1
V=0
V=+1
V=-2
V=+2
CoH infrared electronic transition
Assigned transitions
We have assigned and analyzed:
CoD: A′ 3Φ4─ X 3Φ4: (0,0), (2,0), (1,0), (2,1), (0,1), (1,2),
(2,3), (0,2) and (1,3)
A’ 3Φ3─ X 3Φ3: (0,0)
CoH: A′ 3Φ4─ X 3Φ4: (0,0), (2,0), (1,0), (0,1), (1,2)
A′ 3Φ3─ X 3Φ3 : (0,0)
A′ 3Φ3─ X 3Φ4: (0,0)
A′ 3Φ4─ X 3Φ3: (0,0)
One of the parity components of the X 3Φ3 state is perturbed
in CoH. The only close-lying (according to ab initio
calculations) electronic state that can cause this is a 3Σstate, which has a 0+ component of e parity. This
observation suggests a parity assignment of the lines and
places a 0+ component of 3Σ- state at ~700 cm-1.
Band-by-band fit
The excited electronic state was fit to the term values,
when ground state rotational levels were fit to the following
case (c) expression:
Fυ ( J )  Gυ  Bυ [( J ( J  1) -  2 ] - Dυ [( J ( J  1) -  2 ]2  H υ [( J ( J  1) -  2 ]3  ...
 12 {q υ [( J ( J  1) -  2 ]  q(  1) υ [( J ( J  1) -  2 ] 1  ...}
After that the ground state constants were held fixed to the
well determined values from the previous fit and Watson's
"Robust" data weighting procedure was employed [J. Mol.
Spectrosc. 219, 326 (2003)] in order to obtain reasonable
excited state spectroscopic constants.
X 3Φ4
v=0
v=1
v=2
Tv
0
1855.3720 (70)
3641.6050 (95)
Bv
7.136589 (170)
6.925049 (200)
6.71162 (38)
104 x Dv
4.0100 (100)
4.0644 (110)
3.942 (41)
108x Hv
0.845 (22)
3.33 (22)
5.8 (99)
1011x Lv
-1.340 (170)
-3.440 (150)
-18.20 (25)
1011x qL
-1.175 (110)
2.354 (100)
1.60 (65)
1015x qM
-8.60 (80)
-50.70 (70)
-300 (40)
v=0
v=1
v=2
Tv
12358.4390 (85)
13796.5740 (130)
15136. 047 (150)
Bv
5.47693 (69)
5.28919 (190)
5.1564 (40)
104 x Dv
-4.280 (140)
-3.68 (66)
-8.43 (33)
106x Hv
1.760 (73)
9.33 (75)
6.04 (85)
1011x Lv
-
-6.20 (24)
-
108x qL
1.003 (39)
0.532 (55)
0.472 (99)
1011x qM
-8.30 (35)
-3.10 (28)
-2.01 (53)
A′ 3Φ4
Numbers in parenthesis are 2σ in units of the last digit
Ground and excited state constants
for Ω=3 components (in cm-1)
X 3Φ3 (v=0)
A′ 3Φ3 (v=0)
Tv
675.596 (23)
12644.627 (23)
Bv
7.275947 (31)
6.38186 (110)
103 x Dv
0.5322 (110)
1.2572 (96)
106x Hv
-0.8631 (20)
1.130 (33)
1010x Lv
-
-6.00 (39)
106x qH
-1.6932 (38)
-0.1690 (72)
109x qL
-
2.476 (26)
Combined-isotopologue fit
Apart from Dunham fits of both molecules a combinedisotopologue fit was carried out using the following model:
CoD was chosen as the reference isotopologue, since there is
more vibrational data for that molecule than for CoH
Combined-isotopologue fit
Gv parameters:
YLM( 1,0)= 1373.4492 (120)
YLM( 2,0)= -17.7040 (69)
YLM( 3,0)= 1.600e-02 (110)
Bv parameters:
YLM( 0,1)= 3.758921 (74)
YLM( 1,1)= -7.8664e-02 (59)
YLM( 2,1)= 0.93e-04 (16)
-Dv parameters:
YLM( 0,2)= -1.12315e-04 (240)
YLM( 1,2)= 0.446e-06 (160)
YLM( 2,2)= 1.45e-07 (37)
Hv parameters:
YLM( 0,3)= 2.807e-09 (270)
YLM( 1,3)= -0.268e-09 (150)
Lv parameters:
YLM( 0,4)= -0.485e-13 (110)
YLM( 1,4)= 1.10e-13 (63)
Lambda-doubling Dunham-type
expansion coefficients:
qLM( 0,4) = 3.84e-14 (80)
qLM( 1,4) = -2.018e-13 (120)
qLM( 2,4) = 8.04e-14 (32)
qLM( 0,5) = 0.17e-17 (37)
qLM( 1,5) = -1.50e-17 (26)
Born-Oppenheimer breakdown
parameters:
δ( D; 1,0)= 4.888e-01 (110)
δ( D; 2,0)= -0.33e-02 (27)
δ( D; 0,1)= 7.4231e-02 (81)
δ( D; 1,1)= -1.571e-03 (68)
δ( D; 2,1)= 0.750e-04 (160)
δ( D; 0,2)= -9.372e-06 (140)
δ( D; 1,2)= 4.30e-07 (51)
δ( D; 0,3)= 2.710e-09 (74)
Conclusions and Future Work
• Electronic spectra of CoH and CoD in the red and
infrared were investigated using a Fourier transform
spectrometer. The recorded bands considerably extend
available vibrational and rotational information for the
ground electronic state.
• Ω=±1 transitions were observed for CoH allowing
accurate determination of the spin-orbit splitting between
Ω=4 and 3 components.
• Band-by-band, Dunham and combined-isotopologue fits
were carried out.
• New electronic transitions were observed, but were not
identified yet.
Financial support from NSERC is gratefully acknowledged.