Transcript KRb OSU 2012eyler.pptx

Spectroscopic analysis of the A and 3 1S+
states of 39K85Rb
J. T. Kim1, Y. Lee2, and B. Kim3
1Department
of Photonic Engineering, Chosun University.
2Department of Chemistry, Mokpo National University.
3Department of Chemistry, KAIST.
D. Wang
Department of Physics, The Chinese University of Hong Kong.
J. Banerjee, E. E. Eyler, P. L. Gould, and W. C. Stwalley,
Physics Department, University of Connecticut.
Supported by the National Science Foundation, the Air Force
Office of Scientific Research, the National Research
Foundation of Korea, and KOSEF through NRL in Korea.
Motivations
• Prior MB + UM− work: Combined analysis of molecular beam
(MB) spectra and ultracold molecule spectra based on PA to the 3(0-)
state (UM−): → 1 1P, 2 3S+, and b 3P states.
• MB + UM+ + UM– : Incorporating the prior spectra with new
ultracold spectra based on PA to 3(0+): → the A and 3 1S+ states.
Previously just a few low-v levels were known.
• Determine why the A and 3 1Σ+ states are seen in the UM+ spectra
but not in the UM– spectra.
• Set the path for future investigations of the extended potential well.
• Very new: Assignments of excited-state energy levels enable analysis of new formation schemes for ultracold ground-state molecules
 successful single-laser production of X 1S+ (v = 0 , J = 0).
Experimental scheme for UM– and UM+
(Storrs)
1) PA to form ultracold
KRb*.
Ionization Continuum
REMPI
3(0+)
e  (v , J )
1
1P
2 3S+
3
b 3P
10
K(4S1/2)+Rb(5PJ)
e(v , J )
SE
-1
Energy (X10 cm )
15
3(0-)
PA
3) Spontaneous decay
into both a 3Σ+ and X
1Σ+ after PA to 3(0+):
UM+ experiment
SE
K(4S1/2)+Rb(5S1/2)
5
a 3S+(v, J)
X 1S+(v =0, J )
0
2
4
6
8
10
R (Å)
12
14
16
2) Spontaneous decay
into the triplet a 3Σ+
state after PA to 3(0–):
UM– experiment
18
4) REMPI detection via
intermediate states
e (v , J ) .
Experimental scheme for MB (Korea)
Ionization Continuum
MB RE2PI
e  (v , J )
1 1P
2 3S+
3
-1
Energy (X10 cm )
15
1) Supersonic beam
forms X 1S+ with
v = 0, 1.
K(4S1/2)+Rb(5PJ)
2) REMPI detection
via intermediate
states e (v, J ).
b 3P
10
K(4S1/2)+Rb(5S1/2)
5
a 3S+(v, J)
X 1S+(v =0, J )
0
2
4
6
8
10
R (Å)
12
14
16
18
Combined UM-, UM+ and MB spectra
Ionization Continuum
UM RE2PI
MB RE2PI
K(4S1/2)+Rb(5PJ)
e  (v , J )
1
1P
e(v , J )
2 3S+
3
-1
Energy (X10 cm )
15
• Intermediate states
e (v , J ) can
coincide.
SE
b 3P
10
SE
PA
K(4S1/2)+Rb(5S1/2)
5
a 3S+(v, J)
X 1S+(v =0, J )
0
2
4
6
8
10
R (Å)
12
14
16
18
• Comparison
facilitates
assignments.
Excitation windows
18
WMB
WUM
3
2 P
17
3
-1
Energy (10 cm )
1
2 P
16
Intermediate level
1
1 P
15
1
3 S
UM
+
14
3
2 S
13
+
1
A S
3
b P
+
MB
12
4
6
8
R (Å)
10
12
(a)
Intensity (Arb. Units)
Lower energy portion of the MB spectra
1
1 P1
3
b P1
*
*
*
+
+
+
*
++
+
*
+
1
3 S0
14800
14900
15000
+
+
15100
1) )
Energy
(cm
Energy (cm
-1
Intensity (arb. units)
(b)
1
1 P1
3
2 S1
+
3
b P1
+
*
* *
*
* * *
1
3 S0
15100
15200
Energy (cm1) 15300
Energy (cm-1)
15400
+
+
Overlapping UM and MB spectra,
with assignments
3
2 S
UM–

1
1,0
1 P1
-
3
b P0,1, 2
?
(a)
1
3 S

UM+
v "=89 87
0
+
o
1
A S
o
oo
o
o

0
+
o
o
v a= 21
3
2 S
(c)
o
o
o
o
o
o
o
o
o
o
o
1
3 S
?
o
o
o
o
(b)
MB
?
o
19
1
1 P1

1
b P1
*

0
3
* *
+
15450
15500
15550
-1
Energy(cm )
15600
Transition dipole moment calculations by
Kotochigova, et al.
• TDM is very small between va = 21 of the a 3S+ (W = 1) state (which
has an outer turning point near 17 Å) and the vibrational levels of the A
1S+ (2 1S ) state in our experimental energy region.
0+
• Transitions to the A 1S+ (W = 0+) state are much stronger from v  = 89 of
the X 1S+ (W = 0+) state.
S. Kotochigova, P. S. Julienne, and E. Tiesinga, Phys. Rev. A 68, 022501 (2003).
Effects of the selection rules
and transition dipole moments
Selection Rule: +  +, –  –, + 
/ –.
PA to 3(0+):
• Radiative decay is allowed to the a 3S+(W =1) or X 1S+ (W=0+)
states.
• TDM is large from X 1S+(W=0+) to A and 3 1S+ (W=0 +).
• Transitions are seen to the A and 3 1S+ states (UM+)
PA to 3(0-):
• Can decay only to a 3S+(W = 1, 0– ) not to X 1S+ .
• No transitions to A or 3 1S+ (W = 0 +) from a 3S+ (W = 0– ).
• TDM is small between a 3S+(W=1) and A or 3 1S+ (W = 0+).
• No transitions from a 3S+(W = 1) to the A or 3 1S+ states (UM–)
Vibrational intervals DGv+1/2 from UM+, UMand MB spectra
50
• Some perturbations and scatter
are evident, due to admixture
between states.
• Agreement with theoretical DG
trends for 3 1S is excellent,
even where ion-pair coupling
causes anomalous slow rise.
40
-1
DGv' +1/2 (cm )
• Agreement of overall trends
with theory shows that the
potential energy curves have the
correct shape.
30
1 +
3 S
1 +
3 S (Exp.)
Amiot et al.
1 +
A S (Exp.)
1 +
A S (Rousseau et al.)
1 +
3 S (Rousseau et al.)
20
10
1 +
A S
K(4p)+Rb(5s)
K(4s)+Rb(5p1/2)
0
10000
11000
12000
-1
E(cm )
13000
Characterization of the A and 3 1S+ states
at long range
• Theoretical potentials are
shown in Hund’s case (c), with
spin-orbit, and in case (a),
without spin-orbit.
• The 2 1S+ state crosses diabatically with the b 3P state
near 5.1 Å. The 3(0+) longrange state correlates diabatically mostly with the 3 1S+
state at short range, after
passing through a strong
avoided crossing with another
4(0+) curve at 7.1 Å.
K(4p1/2, 3/2)+Rb(5s)
+
3(0 )
+
2 (0 )
12000
1 +
1 +
A S (2 S )
9000
6000
K(4s)+Rb(5p1/2, 2/3)
9.843 Å
1 +
3 S
-1
Energy(cm )
• The asymptotic 2(0+) state has
an avoided crossing near 5.1 Å
with 3(0+).
+
4 (0 )
5.172 Å
5
10
R(Å)
15
20
FCFs between the X 1S+ (v= 0, 90, and 92)
state and the A 1S+(v) and 3 1S+(v) states.
• (a) FCFs between the X 1S+ (v  =
0, 90, and 92) state and vibrational levels v  of the A 1S+ state.
• In REMPI spectra from high-v 
levels of the ground state (used in
UM experiments), the FCF distribution to levels near the dissociation energy limit is broader
and has larger FCFs compared to
the v  = 0 level (used in MB
experiments).
0.08
v X= 92
v "= 90
FCFs
(a)
0.04
v' = 93
121
K(4s)+Rb(5p3/2)
0.00
0
50
v' =26
100
1 +
A S (v ')
150
200
v' = 52
0.06
FCFs
• (b) FCFs between the X 1S+ (v  =
0 and 90) state and vibrational
levels v  of the 3 1S+ state.
K(4s)+Rb(5p1/2)
v "=0
(b)
0.04
v "=0
0.02
v "= 90
K(4s)+Rb(5p3/2)
0.00
0
20
40
1 +
3 S (v ')
60
80
Application: Identifying ultracold molecules
in low-v levels of the X 1S+ state.
• A long-term goal at UConn
has been efficient one-step
formation of true groundstate molecules, X 1S+ (v = 0,
J  = 0).
• New result: mixed a and X
formation following PA to
J ′=1 of the mixed state 4(1),
v′=61 and 2(1), v′=165.
• Energy levels from the MB
+ UM+ + UM– analysis are
used to assign the 1+1
REMPI spectraon.
REMPI
PA
SE
R (Å)
J. Banerjee, J. T. Kim, E. E. Eyler, P. L. Gould, and W. C. Stwalley, to be published.
REMPI assignments from X 1S+, v=0
X 1S+(v″=0)
to
1 1P (v′ = 0–4)
Blue:
10
8
X 1S+(v″=0)
to
3 1S+(v′ = 27–30)
KRb
+
Green:
6
Red:
4
X 1S+(v″=0)
to
2 3S+(v′ = 37–43)
2
15000
15050
15100
15150
15200
15250
15300
-1
Detection
DetectionLaser
LaserWavenumber
Wavelength (cm-1)
• Numerous transitions from X 1S+, v ″ = 0–10 are observed in this spectrum.
• Roughly 5000 molecules/s formed in X(v ″ =J ″ =0) in an ordinary MOT.
Summary
• New assignments to the perturbed A 1S+ and 3 1S+ states of
39K85Rb are made by comparing UM+, UM– and MB
spectra.
• Good agreement with potential curves from Rousseau et al.
• The presence of the 1Σ+ states in the UM+ spectra and their
absence in UM– spectra can be explained by considering
Hund’s case (c) selection rules and TDM calculations.
• Proposed investigations of the extended potential well by
combining the MB and UM spectra.
• New: one-step formation of X(0,0) by PA in a MOT,
identified using these and earlier MB + UM assignments.