2. hunda: Hund's case (a) diatomics

ElecStateLabel

Description

ElecStateLabel is a label identifying the electronic state: X, A, a, B, etc.

XML element

hunda:ElecStateLabel

Attributes

None.

Restrictions

  • string

elecInv

Description

elecInv is the parity of the electronic wavefunction with respect to inversion through the molecular centre of mass in the molecular coordinate system.

XML element

hunda:elecInv

Attributes

None.

Restrictions

  • 'g' or 'u'

elecRefl

Description

elecRefl is the parity of the electronic wavefunction with respect to reflection in a plane containing the molecular symmetry axis in the molecular coordinate system (equivalent to inversion through the molecular centre of mass in the laboratory coordinate system).

XML element

hunda:elecRefl

Attributes

None.

Restrictions

  • '+' or '-'

|Λ|

Description

|Λ| is the quantum number associated with the magnitude of the projection of the total electronic orbital angular momentum, L, onto the molecular axis.

XML element

hunda:Lambda

Attributes

None.

Restrictions

  • non-negative integer

|Σ|

Description

|Σ| is the quantum number associated with the magnitude of the projection of S onto the molecular axis.

XML element

hunda:Sigma

Attributes

None.

Restrictions

  • non-negative integer or half-odd integer; |Σ| = S, S-1, ..., 0.5 or 0

Ω

Description

Ω is the quantum number associated with the projection of the total angular momentum (excluding nuclear spin), J, onto the molecular axis: Ω = |Λ + Σ| (or Ω = |Λ| + Σ if S > |Λ| > 0).

XML element

hunda:Omega

Attributes

None.

Restrictions

  • non-negative integer or half-integer
  • |Ω| ≤ J

S

Description

S is the quantum number associated with the total electronic spin angular momentum, S.

XML element

hunda:S

Attributes

None.

Restrictions

  • non-negative integer or half-odd integer

v

Description

v is the vibrational quantum number.

XML element

hunda:v

Attributes

None.

Restrictions

  • non-negative integer

J

Description

J is the quantum number associated with the total angular momentum excluding nuclear spin, J.

XML element

hunda:J

Attributes

None.

Restrictions

  • non-negative integer

I

Description

I is a nuclear spin quantum number corresponding to the coupling of the nuclear spin angular momenta of two identical nuclei, I = I1 + I2.

XML element

hunda:I

Attributes

  • nuclearSpinRef: a whitespace delimited list of labels identifying the nuclear spins coupled to form I
  • id: a label identifying the nuclear spin angular momentum, I, formed by this coupling

Restrictions

  • non-negative integer or half-integer

F1

Description

F1 is the intermediate angular momentum quantum number associated with the coupling of the rotational angular momentum and nuclear spin of nucleus 1 where two such couplings are resolved: F1 = J + I1; F1 is often not a good quantum number.

XML element

hunda:F1

Attributes

  • nuclearSpinRef: a label identifying the nuclear spin coupled to J (or F1) to form the total angular momentum

Restrictions

  • non-negative integer or half-integer
  • |J - I1| ≤ F1 ≤ J + I1

F

Description

F is the quantum number associated with the total angular momentum including nuclear spin: F = J + I1 if only one such coupling is resolved, F = F1 + I2 if both couplings are resolved. For identical nuclei, F = F + I, where I is the total nuclear spin angular momentum formed by coupling both spins.

XML element

hunda:F

Attributes

  • nuclearSpinRef: a label identifying the nuclear spin coupled to J (or F1) to form the total angular momentum

Restrictions

  • non-negative integer or half-integer

r

Description

r is a named, positive integer label identifying the state if no other good quantum numbers or symmetries are known.

XML element

hunda:r

Attributes

name: a string identifying this ranking index

Restrictions

  • positive integer

parity

Description

parity is the total parity: the parity of the total molecular wavefunction (excluding nuclear spin) with respect to inversion through the molecular centre of mass of all particles' coordinates in the laboratory coordinate system, the E* operation.

XML element

hunda:parity

Attributes

None.

Restrictions

  • '+' or '-'

kronigParity

Description

kronigParity is the 'rotationless' parity: the parity of the total molecular wavefunction excluding nuclear spin and rotation with respect to inversion through the molecular centre of mass of all particles' coordinates in the laboratory coordinate system. For integer J, total parity is +(-1)J for 'e' states and -(-1)J for 'f' states; for half-integer J, total parity is +(-1)J-1/2 for 'e' states and -(-1)J-1/2 for 'f' states.

XML element

hunda:kronigParity

Attributes

None.

Restrictions

  • 'e' or 'f'

asSym

Description

asSym is (for diatomic molecules with a centre of inversion) the symmetry of the rovibronic wavefunction: 'a' or 's' such that the total wavefunction including nuclear spin is symmetric or antisymmetric with respect to permutation of the identical nuclei (P12), according to whether they are bosons or fermions respectively.

XML element

hunda:asSym

Attributes

None.

Restrictions

  • 's' or 'a'