Atom

Mutiplicity
(2S + 1)

S=1/2 * unpaired electron
(S = total electronic spin)　

unpaired electron

PM3
(kcal/mol)

HF 6-31G*
(kcal/mol)

MP2 6-31G*
(kcal/mol)

H

doublet
(2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s¹

52.1

-312.6

-312.6

He

single
(2 * 0 +1)

1/2 * 0 = 0

0
1s²

N/A

-1791.6

-1798.7

Li

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s¹

-83.8

-4663.3

-4663.3

Be

single
（2 * 0 + 1)

1/2 * 0 = 0

0
1s²2s²

77.0

-9140.9

-9157.4

B

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p¹

135.7

-15387.8

-15410.8

C

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p²

170.9

-23645.1

-23677.8

N

quartet
(2 * 3/2 +1)

1/2 * 3 = 3/2

3
1s²2s²2p³

113.0

-34127.4

-34172.3

O

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p⁴

59.6

-46927.6

-46987.9

F

doublet
(2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁵

18.9

-62352.5

-62429.2

Ne

single
(2 * 0 +1)

1/2 * 0 = 0

0
1s²2s²2p⁶

N/A

-80618.9

-80713.2

Na

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁶3s¹

25.7

-101557.0

-101557.0

Mg

single
（2 * 0 + 1)

1/2 * 0 = 0

0
1s²2s²2p⁶3s²

35.0

-125248.1

-125261.9

Al

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁶3s²3p¹

79.5

-151767.5

-151785.9

Si

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p⁶3s²3p²

108.4

-181244.7

-181269.9

P

quartet
(2 * 3/2 +1)

1/2 * 3 = 3/2

3
1s²2s²2p⁶3s²3p³

75.6

-213786.3

-213821.9

S

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p⁶3s²3p⁴

66.4

-249419.9

-249468.5

Cl

doublet
(2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁶3s²3p⁵

29.0

-288308.0

-288373.5

Ar

single
(2 * 0 +1 )

1/2 * 0 = 0

0
1s²2s²2p⁶3s²3p⁶

N/A

-330555.5

-330641.7

Atom

Mutiplicity
(2S + 1)

S=1/2 * unpaired electron
(S = total electronic spin)　

unpaired electron

PM3
(kcal/mol)

HF 6-31G*
(kcal/mol)

MP2 6-31G*
(kcal/mol)

H⁺

single
（2 * 0 + 1)

1/2 * 0 = 0

0
1s⁰

353.6

0

0

He⁺

doublet
(2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s¹

N/A

-1251.0

-1251.0

Li⁺

single
(2 * 0 +1)

1/2 * 0 = 0

0
1s²

38.4

-4540.4

-4540.4

Be⁺

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s¹

267.3

-8958.0

-8958.0

B⁺

single
（2 * 0 + 1)

1/2 * 0 = 0

0
1s²2s²

232.8

-15207.1

-15228.4

C⁺

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p¹

398.3

-23398.0

-23425.6

N⁺

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p²

419.3

-33805.3

-33839.7

O⁺

quartet
(2 * 3/2 +1)

1/2 * 3 = 3/2

3
1s²2s²2p³

353.9

-46650.7

-46689.5

F⁺

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p⁴

396.9

-61993.0

-62041.6

Ne⁺

doublet
(2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁵

N/A

-80165.4

-80225.9

Na⁺

single
(2 * 0 +1)

1/2 * 0 = 0

0
1s²2s²2p⁶

135.6

-101442.7

-101442.7

Mg⁺

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁶3s¹

217.9

-125095.8

-125095.8

Al⁺

single
（2 * 0 + 1)

1/2 * 0 = 0

0
1s²2s²2p⁶3s²

147.5

-151639.4

-151655.7

Si⁺

doublet
（2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁶3s²3p¹

280.7

-181068.7

-181090.3

P⁺

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p⁶3s²3p²

287.6

-213557.0

-213586.9

S⁺

quartet
(2 * 3/2 +1)

1/2 * 3 = 3/2

3
1s²2s²2p⁶3s²3p³

272.9

-249209.0

-249249.9

Cl⁺

triplet
(2 * 1 + 1)

1/2 * 2 = 1

2
1s²2s²2p⁶3s²3p⁴

282.0

-288036.3

-288089.9

Ar⁺

doublet
(2 * 1/2 + 1)

1/2 * 1 = 1/2

1
1s²2s²2p⁶3s²3p⁵

N/A

-330217.5

-330287.8