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Baer M., Billing G.D. (eds.) - The role of degenerate states in chemistry (Adv.Chem.Phys. special issue, Wiley, 2002)

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646

miljenko peric´ and sigrid d. peyerimhoff

The zeroth-order vibronic level is threefold degenerate, with the wave functions ju u K uþ1 K u þj i j1i; ju u K uþ1 K u 1 þi j2i and ju u 2 K uþ1 K uþ1þi j3i. The zeroth-order energy is given by Eq. (A.18). The first-order energy corrections are

E2ð1Þ ¼ Aso E1ð1=Þ3 ¼ D

where

q

D ¼ 2A2so þ u2 þ t2

The corresponding wave functions are

 

u

 

 

Aso

 

t

 

 

 

 

 

 

 

 

Aso

1

 

 

 

 

 

 

 

 

 

2 ¼ pu2

þ t2 j2i pu2 þ t2 j3i

 

 

 

 

rj i

 

2 rj

i

 

2

u

 

t

t

 

1=3 ¼ p

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

1

 

u

 

1

 

 

Aso

 

1 D 2

 

 

1

D

 

 

p p

 

2

þ

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

p

2

u

 

t

 

rj i

 

 

 

 

 

 

 

 

1

D

3

 

 

 

 

 

 

 

p

2

 

2

 

 

 

 

 

 

 

 

 

 

þ

The second-order energy correction are

E2ð2Þ

¼

1

 

 

8ðuT eT2 oT2 þ uCeC2 oC2 Þ

fuT ðuT þ 1Þ½ðuT þ 2Þe2T o2T þ uCe2Co2C&e2T oT þ uCðuC þ 1Þ½uT e2T o2T þ ðuC þ 2Þe2Co2C&e2CoCg

ðA:22Þ

ðA:23Þ

ðA:24Þ

ðA:25Þ

E1ð2=Þ3 ¼

1

ðuT þ 1Þ 1 þ

 

t2

eT2 oT

1

ðuC þ 1Þ 1

þ

 

u2

eC2 oC

 

8

u2 þ t2

8

u2 þ t2

 

 

Aso

ðuT þ 1Þ

u2

 

uT

eT2 oT þ ðuC þ 1Þ

t2

 

uC

eC2 oC

 

8D

u2 þ t2

u2 þ t2

ðA:26Þ

The formulas for E1=3 are valid also for the case uC ¼ 0: They are identical to (A.17) if in the latter, K is replaced by uT 1.

The Aso ¼ 0 limits of the formulas presented in this subsection cover all particular cases (including uT ¼ 1; uC ¼ 1, and uT ¼ 2; uC ¼ 1) handled in the previous works [18,132,153].

renner–teller effect and spin–orbit coupling

647

APPENDIX B: PERTURBATIVE HANDLING OF THE RENNER–TELLER EFFECT AND SPIN–ORBIT COUPLING INELECTRONIC STATES OF TETRAATOMIC MOLECULES

We restrict ourselves again to symmetric tetraatomic molecules (ABBA) with linear equilibrium geometry. After integrating over electronic spatial and spin coordinates we obtain for electronic states in the lowest order (quartic) approximation the effective model Hamiltonian H ¼ H0 þ H0, which zerothorder part is given by Eq. (A.4) and the perturbative part of it of the form

 

 

 

2p

T

 

 

C

 

 

q

 

 

e

ð

Þ

 

ð

 

 

 

Þ

 

 

 

H0

¼ aT oT qT4 þ aCoCqC4

þ b0poT oCqT2 qC2

 

 

 

 

 

 

 

 

T oT

 

 

 

 

 

2i fT

 

fC

 

CoC

 

 

 

 

 

 

 

þ

b

 

o o

 

 

q2 2

½

 

 

þ

e

2i fT

 

fC

 

&

 

 

 

 

 

 

 

 

T

 

C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

þ

c

 

q4

½

e

 

4ifT

þ

e4ifT

& þ

c

 

 

 

q4

e 4ifC

 

 

 

 

 

T

 

 

 

 

 

 

 

 

 

 

 

 

C

½

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

þ e4ifC & þ cTCpoT oCqT2 qC2 ½e 2ifT e 2ifC

 

 

 

 

 

þ

e2ifT e2ifC

&

2 Aso

 

 

 

 

 

 

 

 

 

 

 

ð

B:1

Þ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The dimensionless parameters aT ; . . . ; cTC appearing in the last expression are connected with the sums and differences of the adiabatic potentials as shown elsewhere [149,150]. This effective Hamiltonian acts onto the basis functions (A.1) with ¼ 2.

The zeroth-order Hamiltonian and the spin–orbit part of the perturbation are diagonal with respect to the quantum numbers K; ; P; uT ; lT ; uC, and lC. The terms of H0 involving the parameters aT ; aC, and b0 are diagonal with respect to both the lT and lC quantum numbers, while the b2 term connects with one another the basis functions with l0T ¼ lT 2; l0C ¼ lC 2. The c terms couple with each other the electronic species and . The selection rules for the vibrational quantum numbers are u0T=C ¼ uT=C; uT=C 2; uT=C 4.

As in the case of electronic states of tetraatomic molecules, because of generally high degeneracy of zeroth-order vibronic leves only several particular (but important) coupling cases can be handled efficiently in the framework of the perturbation theory. We consider the following particular cases:

Case Ba

uC ¼ 0

 

Case Ba1

K ¼ uT þ 2

 

The zeroth-order vibronic wave function is juT uT

0 0 þi. The zeroth-order

energy is

 

 

 

Eð0Þ ¼ ðuT þ 1Þ oT þ oC

ðB:2Þ

648

 

 

 

 

 

 

 

 

 

 

 

 

 

 

miljenko peric´

and sigrid d. peyerimhoff

 

 

 

The firstand second-order energy corrections are

 

 

 

 

 

 

 

 

 

2

¼ ðu1

þ

 

Þðu

T

þ

 

 

Þ

o

þ

 

o

 

2þ ðu þ

2 Þ

 

 

þ

2 Aso

 

 

 

Eð1Þ

 

 

T

 

 

 

1

 

 

 

 

2 aT T

 

 

2aC C

 

 

 

 

 

T

 

1 b0poT oC

 

 

 

 

Eð Þ ¼

 

 

 

 

ðuT þ 1ÞðuT þ 2Þð4uT þ 9ÞaT oT 9aCoC

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

2

ðuT þ 1ÞoT þ oC þ

 

oT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ðuT þ 1Þb0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

oT þ oC

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT oC

 

 

 

 

 

oT oC

 

 

 

 

b2 4uT oT þ ½ðuT þ 1ÞðuT þ 2Þ þ

2&

 

 

 

þ uT ðuT 1Þ

 

 

 

 

 

oT þ oC

oC oT

 

 

 

 

1ð

 

þ

 

Þð

uT

þ

Þ

 

 

 

 

 

 

 

ð 2

þ

Þ

2

 

 

ð

Þ

 

 

 

2 uT

 

 

1

 

 

 

2 aT b0poT oC

 

 

4 uT

 

 

1 aCb0poT oC

 

B:3

 

 

 

 

 

 

 

ðuT þ 1ÞðuT þ 2ÞðuT þ 3ÞðuT þ 4ÞcT oT 6cCoC

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

oT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ðuT þ 1ÞðuT þ 2ÞcTC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT þ oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Case Ba2

 

 

 

 

K ¼ uT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The zeroth-order wave function is juT

uT 2 0 0 þi

 

 

 

 

 

 

2

¼

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

2

 

 

 

þ 2 Aso

 

 

 

Eð1Þ

 

uT ðuT

 

þ 5ÞaT oT þ 2aCoC þ ðuT þ 1Þb0poT oC

 

 

 

Eð Þ ¼

 

 

uT ðuT þ 1Þð4uT þ 35ÞaT oT 9aCoC

 

 

 

 

 

 

 

 

 

 

 

2

þ oC þ ð

oC oT

 

 

 

 

 

2 0 ðuT þ

 

 

Þ

oT þ ðuT þ

 

 

ÞoC

þ oT

 

 

 

 

 

 

 

1

b2

 

 

 

 

 

 

1

2

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

2uT oT oC

 

uT

1ÞoT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b2 ð12uT 8ÞoT þ ðuT

þ uT

þ

6Þ

 

 

 

 

 

 

 

ðB:4Þ

 

 

oT þ oC

 

 

 

 

 

 

þ ðuT 1ÞðuT

2Þ

 

oT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oC oT

 

 

ð

uT

2þ

 

Þ

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

ðu

 

 

þ

 

Þ

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

2uT

 

 

T

 

 

5

 

aT b0poT oC

 

4

 

 

 

 

1

 

aCb0poT oC

 

 

 

 

 

 

 

 

 

uT ðuT þ 1ÞðuT þ 2ÞðuT þ 35ÞcT oT 6cCoC

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

cTC 4uT oT

þ uT ðuT þ 1Þ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oC þ oT

 

 

 

 

 

 

 

 

 

 

 

 

 

Case Ba3 K < uT

renner–teller effect and spin–orbit coupling

649

The zeroth-order energy level is twofold degenerate. The corresponding vibronic basis functions are juT K þ2 0 0 i j1i and juT K 2 0 0 þi j2i. The first-order energy correction is

1=2 ¼

2

ð

T þ

 

u

 

 

Þ

o

 

þ

 

þ ðu

 

þ

 

Þ

 

2

 

ð

 

Þ

Eð1Þ

1

3u2

6

 

T

 

K2 aT

 

T

 

2aCoC

 

T

 

1

 

b0poT oC

1

D

 

B:5

 

 

 

 

 

 

 

 

 

 

 

 

where

q

 

 

 

 

ð

 

Þ

D ¼

16ðKaT oT þ AsoÞ2 þ 9ðuT2 K2Þ½ðuT þ 2Þ2 K2&cT2 oT2

 

 

 

B:6

 

The corresponding vibronic wave functions are of the form (A.13) and

(A.14) with D given by (B.6) and

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B ¼ 4ðKaT oT þ AsoÞ

 

 

 

 

 

 

 

ðB:7Þ

The second-order energy corrections are of the form

 

 

 

 

 

 

 

 

 

 

 

 

 

 

E1ð2Þ ¼ c112 H11 þ c122 H22 þ 2c11c12H12

 

 

 

ðB:8Þ

 

 

 

 

 

 

E2ð2Þ ¼ c212 H11 þ c222 H22 þ 2c21c22H12

 

 

 

where

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H11=22 ¼

1

ðuT

þ 1Þ½17uT

ðuT þ 2Þ 9KðK 4Þ&aT2 oT 9aC2 oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

1

b02 4ðuT

þ 1Þ2oT þ 4ðuT þ 1ÞoC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

2

 

 

oT oC

 

 

 

 

 

 

 

 

 

oT oC

 

 

þ ½uT ðK 2Þ &

 

 

 

þ ðuT

KÞðuT k þ 4Þ

 

 

 

 

 

 

oC oT

oC þ oT

 

 

 

1

b22 4½uT ðuT þ 2Þ KðK 4Þ 4&oT þ ½uT ðuT

2Þ

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

þ KðK 4Þ þ 4&

 

 

oT oC

 

 

þ ½uT ðuT þ 6Þ þ KðK

4Þ þ

12&

 

 

oT oC

 

oC oT

 

oC þ oT

 

1½ u ð

uT

þ

Þ

ð 2

 

 

 

Þ&

 

ð

uT

þ

Þ

 

2

 

 

 

3 T

 

2

 

K K

4 aT b0poT oC

4

 

1 aCb0poT oC

 

 

 

 

ðuT þ 1Þð2 KÞcT oT ½17uT ðuT þ 2Þ 3Kð5K 12Þ& 6cCoC

 

 

8

 

 

 

1 2

 

 

 

 

ÞðuT K þ 2ÞoT þ ðuT KÞðuT

 

 

 

 

 

oT oC

 

 

 

 

cTCf4ðuT K

K þ 2Þ

 

 

4

oC oT

þ ðuT KÞðuT K þ 2Þ

 

 

 

oT oC

 

 

 

 

 

 

 

 

 

 

ðB:9Þ

oC þ oT

 

 

 

 

 

 

 

 

 

650

miljenko peric´ and sigrid d. peyerimhoff

 

 

 

and

q

 

 

 

 

 

 

 

 

 

 

 

 

17

 

 

 

 

 

 

 

 

 

H12 ¼

ðuT2 K2Þ½ðuT þ 2Þ2 K2&

ðuT þ 1ÞaT cT oT

 

 

 

 

 

 

 

 

2

oT

ðB:10Þ

þ 3b0cT poT oC þ

2 b2cTC 4oT þ oC

 

oT

þ oC

þ

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT oC

 

oT oC

 

 

If we put oT ¼ o; oC ¼ 0; aT ¼ a; cT ¼ c; aC ¼ b0 ¼ b2 ¼ cC ¼ cTC ¼ 0 all the formulas for case (Ba) reduce to those describing the R–T effect in triatomic molecules.

Case Bb K ¼ uT þ uC þ 2ð¼ KmaxÞ

The zeroth-order vibronic wave function is juT uT uC uC þi. The zerothorder energy is

 

 

 

 

 

 

 

 

Eð0Þ ¼ ðuT þ 1ÞoT þ ðuC þ 2ÞoC

ðB:11Þ

The firstand second-order energy corrections are

 

 

 

 

 

 

Eð1Þ ¼ ðuT þ 1ÞðuT þ 2ÞaT oT þ ðuC þ 1ÞðuC þ 2ÞaCoC

 

1

 

 

 

þ ðuT þ 1ÞðuC þ

 

 

þ 2 Aso

ðB:12Þ

 

 

 

 

 

 

 

1Þb0poT oC

Eð2Þ ¼

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

ðuT þ 1ÞðuT þ 2Þð4uT þ 9ÞaT2 oT

 

ðuC

þ 1ÞðuC þ 2Þð4uC þ 9ÞaC2 oC

2

2

 

1

b0ðuT

þ 1ÞðuC þ 1Þ ðuT þ

1ÞoT þ ðuC þ 1ÞoC þ

oT oC

 

2

oC þ oT

b22 2uT ðuC þ 1ÞðuC þ 2ÞoT þ 2uCðuT þ 1ÞðuT þ 2ÞoC

 

þ ðuT uCÞð2uT uC þ uT þ uC 1Þ

oT oC

 

 

 

 

 

oC oT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT oC

 

þ ½ðuT þ

1ÞðuT þ 2Þ þ ðuC þ 1ÞðuC þ 2Þ&

 

 

 

 

oC þ oT

 

2ðuT þ

 

 

 

 

 

 

 

 

 

 

 

 

1ÞðuT þ 2ÞðuC þ 1ÞaT b0poT oC

 

 

 

 

 

 

1ð

uT

þ

Þð

þ

1

Þð

þ Þ

 

2

 

 

 

 

 

 

2

 

 

 

1 uC

 

uC

2 aCb0poT oC

 

 

 

 

 

 

 

ðuT þ 1ÞðuT þ 2ÞðuT þ 3ÞðuT þ 4ÞcT oT

 

 

 

 

 

4

 

 

 

 

 

 

1

 

ðuC þ 1ÞðuC þ 2ÞðuC þ 3ÞðuC þ 4ÞcC2 oC

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

2

 

 

oT oC

 

 

 

 

ðuT þ 1ÞðuT þ 2ÞðuC þ 1ÞðuC þ 2ÞcTC

 

 

ðB:13Þ

2

 

oC þ oT

renner–teller effect and spin–orbit coupling

651

For uC ¼ 0, the formulas (B.12) and (B.13) reduce to (B.3).

Case Bc K ¼ uT þ uCð¼ Kmax 2ÞuC > 0

The zeroth-order level is twofold degenerate. The corresponding vibronic basis functions are juT uT uC uC 2 þi j1i and juT uT 2uC uC þi j2i. The zeroth-order energy is (B.11). The first-order energy correction is

E1ð1=Þ2 ¼ ðuT2 þ 4uT þ 1ÞaT oT þ ðuC2 þ 4uC þ 1ÞaCoC

 

 

 

þ ð

uT

þ

1

Þð

uC

þ

1

Þ

 

 

 

þ

2 Aso

ð

B:14

Þ

2

 

 

 

 

 

 

b0poT oC

1 D

 

 

 

where

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

q

ð

 

Þ

D ¼ 2 ½ðuT 1ÞaT oT ðuC 1ÞaCoC&2 þ 16uT uCb22oT oC

 

B:15

 

The corresponding wave functions have the form (A.13) and (A.14). In the present case, D is given by (B.15) and

 

 

 

 

 

 

 

 

 

B ¼ 2ðuT 1ÞaT oT þ 2ðuC 1ÞaCoC

 

 

 

 

 

 

ðB:16Þ

The second-order energy corrections have the form (B.8) with

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H11 ¼

 

 

ðuT þ 1ÞðuT

þ 2Þð4uT þ 9ÞaT2 oT

 

 

uCðuC þ 1Þð4uC þ 35ÞaC2 oC

 

2

2

 

 

1

 

 

2

 

 

þ 1Þ ðuT þ 1ÞðuC þ 1ÞoT

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

oT oC

 

 

 

b0ðuT

þ ðuC þ 1Þ

oC ðuC 1Þ

 

 

 

2

oC oT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oT oC

 

 

 

2

2

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

þ

2uC

oC þ oT

b2 2ðuT uC 2uT þ 7uT uC 6uT þ 6uC

4ÞoC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

2

 

 

 

 

 

 

 

 

oT oC

 

 

 

 

 

 

 

 

þ 2uT uCðuC þ 1ÞoT þ ð3uT

þ uC þ

9uT þ uC þ 6Þ

 

 

 

 

 

 

 

 

 

 

 

oC þ oT

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

2

 

 

 

2

 

2

 

 

 

 

 

 

 

 

 

 

oT oC

 

 

 

 

þ ð2uT uC

2uT uC

uT

uC þ 4uT uC 3uT þ

3uC 2Þ

 

 

 

oC oT

 

 

 

1ð

uT

þ

1

Þð

uT

þ

2

Þð

uC

þ

Þ

2

 

1

ð

uT

þ

Þð

 

þ

5

Þ

 

 

2

 

2

 

 

 

 

 

 

1 aT b0poT oC

 

2uC

 

1

 

uC

 

 

aCb0poT oC

 

4 ðuT þ 1ÞðuT þ 2ÞðuT þ 3ÞðuT þ 4ÞcT oT 4 uCðuC þ 1ÞðuC þ 2ÞðuC þ 35ÞcCoC

 

1 2

oT oC

 

 

 

 

cTCuCðuT þ 1ÞðuT þ 2Þ 4oC þ ðuC þ 1Þ

 

 

ðB:17Þ

2

oC þ oT

652

 

miljenko peric´

and sigrid d. peyerimhoff

 

and

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H12 ¼ puT uCf12ðuT þ 1ÞaT b2poT oC þ 12ðuC þ 1ÞaCb2poT oC

 

þ b0b2 4ðuT þ

1ÞoT þ 4ðuC þ 1ÞoC þ ðuT þ uC þ 2Þ

oT oC

 

oC þ oT

 

 

 

4 uC

1 uC

2 cCcTCpoT oC

 

B:18

 

 

 

oT oC

 

þ 2ÞcT cTCpoT oC

 

þ ðuT uCÞ

oC

oT

þ 4ðuT þ 1ÞðuT

 

þ ð þ

Þð

þ Þ

g

ð

Þ

The expression for H22 is obtained by interchanging indexes T and C on the right-hand side of Eq. (B.17) (cCT cTC). For uC ¼ 0; E2ð2Þ ¼ H22 and the second-order energy formula for E2 reduces to that derived for the case Ba2.

Case Bd uT ¼ 1; uC ¼ 1; K ¼ 0

In other cases, the zeroth-order vibronic levels are generally more than twofold degenerate and the perturbative handling is much more complicated. An exception is the case uT ¼ 1; uC ¼ 1; K ¼ 0 with the twofold degenerate zeroth-order level. The basis functions are j1 1 1 1 i j1i and j1 1 1 1 þi j2i. The zeroth-order energy is

 

Eð0Þ ¼ 2oT þ 2oC

 

 

 

ðB:19Þ

The first-order energy correction is

 

 

 

 

 

 

 

1=2 ¼

o þ

o þ

 

2

 

ð

 

Þ

Eð1Þ

6aT T

6aC C

4b0poT oC

 

1

D

 

B:20

 

 

 

 

 

where

q

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D ¼ 4 2Aso2 þ 4cTC2 oT oC

 

 

 

ðB:21Þ

The second-order energy correction is

D H12

 

 

 

 

 

 

 

E1ð2=Þ2 ¼ H11

 

 

 

ðB:22Þ

 

 

 

8cTCpoT oC

 

 

 

 

 

 

 

renner–teller effect and spin–orbit coupling

653

with

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

2

 

 

 

2

 

 

 

 

 

oT oC

 

H11 ¼ 39aT oT

39aCoC

2b0 2oT þ 2oC

þ

 

 

 

 

 

 

oC þ oT

 

2

 

 

 

þ

 

 

 

 

 

 

 

 

oT oC

 

24aT b0poT oC 24aCb0poT oC

12b2 oT þ oC þ

oC

 

 

oT

2

 

2

 

 

 

2

 

 

 

 

 

oT oC

 

54cT oT 54cCoC

2cTC 2oT þ 2oC þ

 

 

 

 

ðB:23Þ

oC þ oT

 

 

8b0cTCoT

 

 

8b0cTCoC

 

4b0cTC oT o

B:24

H12 ¼ 24ðaT cTC

þ aCcTC þ 2b2cT þ 2b2cCÞpoT oC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C

 

ð Þ

 

 

 

 

 

 

 

 

oC þ oT

 

 

 

 

 

 

 

 

 

 

 

 

 

Acknowledgments

We wish to thank all our colleagues who collaborated with us in the calculations presented in the calculations presented in this chapter. One of us (M.P.) likes to thank the Deutsche Forschungsgemeinschaft for financial support.

References

1.P. Jensen and P. R. Buenker, eds., Computational Molecular Spectroscopy, John Wiley and Sons, Inc., 2000.

2.P. Jensen, G. Osmann, and P. R. Buenker, in Computational Molecular Spectroscopy, P. Jensen and R. J. Bunker, eds., John Wiley & Sons, Inc., New York 2000, p. 485.

3.J. M. Brown, in Computational Molecular Spectroscopy, P. Jensen and R. J. Bunker, eds., John Wiley & Sons, Inc., New York 2000, p. 517.

4.G. Herzberg and E. Teller, Z. Phys. Chem. (B) 21, 410 (1933).

5.G. Herzberg, Moleculer Spectra and Molecular Structure III. Electronic Spectra of Polyatomic Molecules, Van Nostrand, New York, 1967.

6.M. Born and R. Oppenheimer, Ann. Phys (Leipzig) 84, 457 (1927).

7.R. Renner, Z. Phys. 92, 172 (1934).

8.Ch. Jungen and A. J. Merer, in Molecular Spectroscopy, Modern Research, K. N. Rao, ed., Vol. 2, Academic Press, New York, 1977, p. 127.

9.K. Dressler and D. A. Ramsay, J. Chem. Phys. 27, 971 (1957).

10.K. Dressler and D. A. Ramsay, Philos. Trans. R. Soc. Ser. A 251, 553 (1958).

11.G. Duxbury, Molecular Spectroscopy, Vol. 3, Billing & Sons, Guilford and London, 1975, p. 497.

12.J. M. Brown and F. Jørgensen, in Advances in Chemical Physics, I. Prigogine and S. A. Rice, eds., John Wiley & Sons, Inc., New York, 1983, Vol. 52, p. 117.

13.H. Ko¨ppel, W. Domcke, and L. S. Cederbaum, Advances in Chemical Physics, I. Prigogine and A. C. Rice, eds., John Wiley, New York, 1986, Vol. 67, p. 59.

14.H. Ko¨ppell and W. Domcke, Encyclopedia of Computational Chemistry, P. V. R. Schleyer et al., eds., Wiley, New York, 1999, p. 3166.

654

miljenko peric´ and sigrid d. peyerimhoff

15.P. R. Buenker and P. Jensen, Molecular Symmetry and Spectroscopy, NCR Research Press, Ottawa, 1998.

16.M. Peric´, S. D. Peyerimhoff, and R. J. Buenker, Int. Rev. Phys. Chem. 4, 85 (1985).

17.M. Peric´, B. Engels, and S. D. Peyerimhoff, Quantum Mechanical Electronic Structure Calculations with Chemical Accuracy, S. R. Langhoff, ed., Kluwer, Dordrecht, 1995, p. 261.

18.M. Peric´, B. Ostojic´, and J. Radic´-Peric´, Phys. Rep. 290, 283 (1997).

19.J. M. Brown, J. Mol. Spectrosc. 68, 412 (1977).

20.R. J. Buenker, M. Peric´, S. D. Peyerimhoff, and R. Marian, Mol. Phys. 43, 987 (1981).

21.M. Peric´, S. D. Peyerimhoff, and R. J. Buenker, Mol. Phys. 49, 379 (1983).

22.W. Pauli, Z. Phys. 43, 601 (1927); G. Breit, Phys. Rev. 34, 553 (1930).

23.B. A. Hess, C. M. Marian, and S. D. Peyerimhoff, Advanced Series in Physical Chemistry: Modern Electronic Structure Theory, C.-Y. Ng and D. R. Yarkony, eds., Singapore: World Scientific, 1995 p. 152; B. A. Hess and C. M. Marian, in Computational Molecular Spectroscopy,

P.Jensen and P. R. Bunker, eds., John Wiley & Sons, Inc., 2000, p. 169.

24.Ch. Jungen and A. J. Merer, Mol. Phys. 40, 1 (1980).

25.Ch. Jungen, K-E. J. Hallin, and A. J. Merer, Mol. Phys. 40, 25 (1980).

26.Ch. Jungen, K-E. J. Hallin, and A. J. Merer, Mol. Phys. 40, 65 (1980).

27.Ch. Jungen and A. J. Merer, Mol. Phys. 40, 95 (1980).

28.M. Peric´, M. Krmar, J. Radic´- Peric´, and Lj. Stevanovic´, J. Mol. Spectrosc. 208 271 (2001).

29.M. Peric´ and M. Krmar, J. Serb. Chem. Soc. 66 613 (2000).

30.S. A. Beaton, Y. Ito, and J. M. Brown, J. Mol. Spectrosc. 178, 99 (1996).

31.S. A. Beaton and J. M. Brown, J. Mol. Spectrosc. 183, 347 (1997).

32.J. T. Hougen, J. Chem. Phys. 36, 1874 (1962).

33.M. Peric´, S. D. Peyerimhoff, and R. J. Buenker, Can. J. Chem. 59, 1318 (1981).

34.M. Peric´ and M. Krmar, Bull. Soc. Chim. Beograd. 47, 43 (1982).

35.R. N. Dixon, Mol. Phys. 9, 357 (1965).

36.C. F. Bender and H. F. Schaefer, III, J. Mol. Spectrosc. 37, 423 (1971); V. Staemmler and

M.Jungen, Chem. Phys. Lett. 16, 187 (1972).

37.G. Herzberg and J. W. C. Johns, Proc. R. Soc. London Ser. A 298, 142 (1967).

38.C. Eckart, Phys. Rev. 47, 552 (1935).

39.E. B. Wilson and J. B. Howard, J. Chem. Phys. 4, 269 (1936).

40.E. B. Wilson, E. B. Decius, and P. C. Cross, Molecular Vibrations, McGraw-Hill, New York, 1955.

41.J. K. G. Watson, Mol. Phys. 15, 479 (1968).

42.J. K. G. Watson, Mol. Phys. 19, 465 (1970).

43.A. R. Hoy, I. M. Mills, and G. Strey, Mol. Phys. 24, 1265 (1972).

44.J. Tennyson, B. T. Sutcliffe, J. Mol. Spectrosc. 101, 71 (1983).

45.D. Estes and D. Secrest, Mol. Phys. 59, 569 (1986).

46.H. Wei and T. Carrington, Jr., J. Chem. Phys. 107, 2813 (1997); 107, 9493 (1997).

47.M. Mladenovic´, J. Chem. Phys. 112, 1070 (2000); 112, 1082 (2000), 113, 10524 (2000).

48.S. Carter and N. C. Handy, Mol. Phys. 47, 1445 (1982).

49.S. Carter, N. C. Handy, and B. T. Sutcliffe, Mol. Phys. 49, 745 (1983).

50.S. Carter and N. C. Handy, Mol. Phys. 52, 1367 (1984).

renner–teller effect and spin–orbit coupling

655

51.S. Carter, N. C. Handy, P. Rosmus, and G. Chambaud, Mol. Phys. 71, 605 (1990).

52.G. D. Carney, L.L Sprandel, and C. W. Kern, Adv. Chem. Phys. 37, 305 (1968).

53.E. K. C. Lai, Master’s Thesis, Department of Chemistry, Indiana University, Bloomington, IN, 1975.

54.B. Podolsky, Phys. Rev. 32, 812 (1928).

55.P. R. Bunker and P. Jensen, Molecular Symmetry and Spectroscopy, NRC Research Press, Ottawa. 1998.

56.M. Peric, M. Mladenovic, S. D. Peyerimhoff, and R. J. Buenker, Chem. Phys. 82, 317 (1983).

57.J. H. Van Vleck, Rev. Mod. Phys. 23, 213 (1951).

58.J. M. Brown and B. J. Howard, Mol. Phys. 31, 1517 (1976).

59.R. N. Zare, Angular Momentum, John Wiley & Sons, Inc., 1988.

60.J. T. Hougen, P. R. Bunker, and J. W. C. Johns, J. Mol. Spectrosc. 34, 136 (1970).

61.P. R. Bunker and J. M. R. Stone, J. Mol. Spectrosc. 41, 310 (1972).

62.A. R. Hoy and P. R. Bunker, J. Mol. Spectrosc. 52, 439 (1974).

63.P. R. Bunker and B. M. Landsberg, J. Mol. Spectrosc. 67, 374 (1977).

64.A. R. Hoy and P. R. Bunker, J. Mol. Spectrosc. 74, 1 (1979).

65.P. Jensen and P. R. Bunker, J. Mol. Spectrosc. 118, 18 (1986).

66.P. Jensen, J. Mol. Spectrosc. 128, 478 (1988).

67.P. Jensen, J. Chem. Soc. Farady. Trans. 2 84, 1315 (1988).

68.A. Sayvetz, J. Chem. Phys. 7, 383 (1939).

69.J. A. Pople and H. C. Longuet-Higgins, Mol. Phys. 1, 372 (1958).

70.A. D. Walsh, J. Chem. Soc. 2260, (1953).

71.J. A. Pople, Mol. Phys. 3, 16 (1960).

72.J. T. Hougen, J. Chem. Phys. 36, 519 (1962).

73.A. J. Merer and D. N. Travis, Can. J. Phys. 43, 1795 (1965).

74.R. Barrow, R. N. Dixon, and G. Duxbury, Mol. Phys. 27, 1217 (1974).

75.K. F. Freed and J. R. Lombardi, J. Chem. Phys. 45, 591 (1966).

76.J. W. Cooley, Math. Comp. 15, 363 (1961).

77.I. Dubois, G. Duxbury, and R. N. Dixon, J. Chem. Soc. Faraday Trans. 2, 71, 799 (1975).

78.G. Duxbury and R. N. Dixon, Mol. Phys. 43, 255 (1981).

79.G. Duxbury, J. Chem. Soc. Faraday Trans. 2, 78, 1433 (1982).

80.G. Duxbury and Ch. Jungen, Mol. Phys. 63, 981 (1988).

81.A. Alijah and G. Duxbury, Mol. Phys. 70, 605 (1990).

82.G. Duxbury, A. Alijah, and R. Trieling, J. Chem. Phys. 63, 981 (1993).

83.G. Duxbury, B. McDonald, and A. Alijah, Mol. Phys. 89, 767 (1996).

84.G. Duxbury, B. McDonald, M. Van Gogh, A. Alijah, CH. Jungen, and H. Palivan, J. Chem. Phys. 108, 2336 (1998).

85.G. Duxbury, A. Alijah, B. McDonald, and Ch. Jungen, J. Chem. Phys. 108, 2336 (1998).

86.M. Peric´, R. J. Buenker, and S. D. Peyerimhoff, Mol. Phys. 59, 1283 (1986) .

87.W. Reuter, M. Peric´, and S. D. Peyerimhoff, Mol. Phys. 74, 569 (1991).

88.M. Brommer, B. Weis, B. Follmeg, P. Rosmus, S. Carter, N. C. Handy, H.-J. Werner, and P. J. Knowles, J. Chem. Phys. 98, 5222 (1993).