S. No.

Symbol

Description

Definition

1) In-plane vibrations (a' species) Stretching

1 - 6

d_i

C-C (ring)

C1-C2, C2-C3, C3-C4, C4-C5, C5-C6, C6-C1

7

r_i

C-C_a (acid)

C1-C7

8

,,

C-C' (methyl)

C4-C15

9 - 11

,,

C-H (ring)

C2-H11, C5-H19, C6-H20

12

,,

C-N

C3-N12

13 - 15

R_i

C-H (methyl)

C15-H16, C15-H17, C15-H18

16

D_i

C_a=O

C7-O8

17

,,

C_a-OH

C7-O9

18

,,

O-H

O9-H10

19 - 20

E_i

N=O

N12-O13, N12-O14

Bending

21 - 26

q_i

C-C-C (ring)

C6-C1-C2, C1-C2-C3, C2-C3-C4, C3-C4-C5, C4-C5-C6, C5-C6-C1

27 - 32

f_i

C-C-H (ring)

C1-C2-H11, C3-C2-H11, C4-C5-H19, C6-C5-H19, C5-C6-H20, C1-C6-H20,

33 - 35

e_i

C-C-H (methyl)

C4-C15-H16, C4-C15-H17, C4-C15-H18

36 - 38

a_i

H-C-H

H16-C15-H17, H16-C15-H18, H16-C15-H18

39

l_i

C-C_a=O

C1-C7-O8

40

,,

C-C_a-O

C1-C7-O9

41

,,

O-C_a=O

O8-C7-O9

42

,,

C_a-O-H (acid)

C7-O9-H10

43 - 44

β_i

C-C-C_a (acid)

C6-C1-C7, C2-C1-C7

45 - 46

,,

C-C-C' (methyl)

C3-C4-C15, C5-C4-C15

47 - 48

,,

C-C-N

C2-C3-N12, C4-C3-N12

49 - 50

y

C-N-O

C3-N12-O13, C3-N12-O14

51

y_i

O-N-O

O13-N12-O14

1) Out-of-plane vibrations (a" species) Wagging

52 - 54

g_i

p(CH)

C1-C2-C3-C11, C4-C5-C6-C19, C5-C6-C1-H20

55

,,

p(CC_a)

C6-C1-C2-C7

56

,,

p(CC')

C3-C4-C5-C15

57

,,

p(CN)

C2-C3-C4-N12

58

w_i

w(OH)

C1-C7-O9-H10

59

,,

w(C_a=O)

C6-C1-C7-O9

Torsion

60 - 65

d_i

τ (ring)

C1-C2-C3-C4, C2-C3-C4-C5, C3-C4-C5-C6, C4-C5-C6-C1,

C5-C6-C1-C2, C6-C1-C2-C3

66

τ_i

τ(CC_a)

C2-C1-C7-O8

67

,,

τ(CC¢)

C3-C4-C15-H18

68 - 69

,,

τ(CN)

C2-C3-N12-O14, C4-C3-N12-O13

70 - 71

w_i

w(NO₂)

C3-N12-O14-O13, C3-N12-013-O14