Zeeman Spectroscopy of CaH

Jinhai Chen, J. Gengler &T. C.

Steimle,

The 60th International Symposium on Molecular Spectroscopy

Interpretation: gaining magnetic moment from A2state

Observation: X2 gs=2.0023; gl= -0.0045

2) Matrix isolated Electron spin resonance Knight& Weltner, J. Chem. Phys. 54, 3875 (1971)

3) Magnetic trapping analysisFriedrich et al J. Chem. Phys. 110, 2376 (1999)

Observation: R1(0.5) (0,0)B2X2 line from 0-26kG

Observation: “anomalous” Zeeman splitting in (0,0)B2X2

Interpretation: interaction with J=1.5,A2(v=1)level

J=1.5,A23/2(v=1)

N=1,J=1.5 B2+(v=0)

Doyle’s group model (JCP 110, 2376 (1999)

N=0,J=0.5 X2+(v=0)

R1(0.5)<A23/2(v=1)|L+| B2(v=1)> =0.40Too large; Unrealistic !!

HZee= mB withmL = -BgLL, mS = -BgSS

Goal of present studyModel and interpret the Zeeman splitting in all transitions

of the (0,0)B2X2and (0,0) A2-X2 bands

gl =-0.0045

HZee(Eff)= -BBz(gLL+gSS) +gl[SxBx+SyBy] +gl’[e-2iS+B++e-2iS-B-]

High-resolution spectrometer

Electromagnet

Optical Zeeman Spectroscopy

Electromagnet for Zeeman spectroscopy (0G-2.5kG)

Mirror

Zeeman effect:SR21(0.5) (0,0) A23/2-X2+

with gl & gl’

without gl & gl’

(v=0)A23/2

(v=0)X2

Zeeman effect:R1(0.5) (0,0) A21/2-X2+

with gl & gl’

without gl & gl’ (v=0)A21/2

(v=0)X2

AB

C D

Low-resolution LIF B2+(v=0)/A2r(v=1) X2+(v=0)

(viewed through a 640 nm bandpass filter)

Next slide**

*

*=measured

R1(0.5) LIF B2+(v=0)/A2r(v=1) X2+(v=0)Feature used by Doyle et al for magnetic field measurements

(640 nm bandpass filter)

Zeeman effect:R1(0.5) (0,0) B2-X2+

with interaction

without interaction

A B C D

This splitting used to measure field in mag. trap

Modeling the field freeA2r(v=1)/B2+(v=0) -X2+ band

Generate “supermatrix” representation– Use effective hamiltonian for v=0 interactions:

B2+ terms (4x4) :

Heff (2+) = BN2 - DN4 + NS + bFIS + c(IzSz-IS)A2(v=0) terms (8x8 matrix):

Heff (2) =Tv + ALzSz + ½AD [N2LzSz+ LzSzN2] + BN2 -D(N2)2 + ½(p+2q)(e-2iJ+S+ + e+2iJ-S-) -½q(e-2i+ e2i)

- use explicit terms for v= 1 interactions:

{(-1)q(A+2B)Tq(L)Tq(S)-2BTq(J)Tq(L)}- Interaction parameters:

M1=

- M2=

)0v()1v( 22 BBLA

)0v()1v( 22 BLB A/2A

Modeling the A2/B2+ Field free interaction

12x12Matrix

Determined “field free” parameters fromA2r(v=1)/B2+(v=0) X2+ band analysis

M2 constrained to =0

Note : -doubling in A2(v=1) approximately =A2(v=0) & approximately = of B2+

(v=0)

Standard deviation of the fit: 0.003 cm-1.

(A 2) (v=1)/

(B 2+)(v=0)

(A 2) (v=0)

B (B 2+) 4.41263(14)

(B 2+) -0.7957(12)

D (B 2+) 0.00023(7)

A (A 2 80.256(2)

B (A 2) 4.21144(7)

A D (A 2) (v=1) -0.05064(15)

p+2q (A 2)(v=1) -0.9141(6) -0.88336(69)

q (A 2)(v=1) -0.0626(4) -0.06753(17)

M 10.69239(15)

T 0(B 2+)d 753.5881(11)

T 1(A 2)d 725.2329(8)

Two adjustable parameters: gl and <(v=1)2|L+|(v=0)B2>

Two adjustable parameters: gl and gl’

-0.09a

-0.04b

gl

’gl

(v=0)A2

Exp.

-0.19(4)

Corr.coef.

0.31

-0.03(1)

Model

a) gl’ = p/2Bb) gl = -/2B (lower limit)

gl

<L+>

(v=0)B2

Exp.

0.22(4)

Corr.coef.

0.31

0.05(1)

Model

0.09a

0.16b

a) gl= -/2Bb)<L+>=< v=1(A2v=0(B2)> x <p+1|L+|p0>

Results

Why we prefer this model over Dolye’s

1. Realistic value for <L+>

2. Works for all transitions (not just R1(0.5))

3. Many internal consistencies are met:

i) gl(B2+) ~ -gl’(A2)

ii) <L+> ~ <AL+>/A etc.

iii) Curl relationships give approx. correct results

Conclusions drawn from the CaH Zeeman studies

1) The Zeeman effect in the A2(v=1)/B2(v=0)-X2(v=0) band system can be modeled with two (one?) adjustable parameters for fields as high as those in the magnetic confinement experiments (approx. 25,000 G!)

2) Sorting out the field-free A2(v=1)/B2(v=0) interaction was crucial to the anlaysis of even the low-field Zeeman spectra.

Funding provided by NSF

Thank You !