Research Article
Molecular Structure and Vibrational Analysis of 1-Bromo-2-Chlorobenzene Using ab initio HF and Density Functional Theory (B3LYP) Calculations
Table 1
Optimized geometrical parameters for 1-bromo-2-chlorobenzene computed at HF/6-31+G (d, p), B3LYP/6-31+G (d, p), and B3LYP/6-31G++ (d, p) basis sets.
| | Geometrical Parameters | Methods | | HF/6-31+G (d, p) | B3LYP/6-31+G (d, p) | B3LYP/6-311++G (d, p) | Experimental value |
| | Bond length (Å) | | | | | | C1–C2 | 1.3865 | 1.400 | 1.397 | — | | C1–C6 | 1.388 | 1.397 | 1.395 | — | | C1–Br11 | 1.8837 | 1.895 | 1.908 | 1.867 | | C2–C3 | 1.388 | 1.398 | 1.395 | — | | C2 –Cl12 | 1.7355 | 1.749 | 1.748 | 1.745 | | C3–C4 | 1.3824 | 1.394 | 1.390 | — | | C3–H7 | 1.0735 | 1.084 | 1.082 | 1.080 | | C4–C5 | 1.3868 | 1.396 | 1.393 | — | | C4–H8 | 1.0748 | 1.085 | 1.083 | 1.080 | | C5–C6 | 1.3828 | 1.394 | 1.390 | — | | C5–H9 | 1.0747 | 1.085 | 1.083 | 1.080 | | C6 –H10 | 1.0735 | 1.084 | 1.082 | 1.080 |
| | Bond angle (°) | | | | | | C2–C1–C6 | 119.3229 | 119.25 | 119.79 | — | | C2–C1–Br11 | 122.2402 | 121.88 | 121.87 | 114.4 | | C6–C1–Br11 | 118.4369 | 118.85 | 118.32 | — | | C1–C2–C3 | 120.2134 | 120.28 | 119.73 | — | | C1–C2–Cl12 | 121.8473 | 121.44 | 121.86 | 116.3 | | C3–C2–Cl12 | 117.9394 | 118.26 | 118.40 | 116.3 | | C2–C3–C4 | 120.1128 | 120.01 | 120.26 | — | | C2–C3–H7 | 119.1113 | 119.08 | 118.83 | — | | C4–C3–H7 | 120.7759 | 120.90 | 120.89 | — | | C3–C4–C5 | 119.9138 | 119.96 | 119.98 | — | | C3–C4–H8 | 119.6402 | 119.56 | 119.51 | — | | C5–C4–H8 | 120.4459 | 120.46 | 120.49 | — | | C4–C5–C6 | 119.8645 | 119.92 | 119.98 | — | | C4–C5–H9 | 120.5147 | 120.54 | 120.52 | — | | C6–C5–H9 | 119.6208 | 119.53 | 119.48 | — | | C1–C6–C5 | 120.5726 | 120.56 | 120.23 | — | | C1–C6–H10 | 119.185 | 119.07 | 119.16 | — | | C5–C6–H10 | 120.2424 | 120.35 | 120.60 | — |
| | Dihedral angle (°) | | | | | | C6–C1–C2–C3 | 0.0 | 0.0 | 0.0 | — | | C6–C1–C2–Br11 | 180.0 | 180.0 | 180.0 | — | | Br11–C1–C2–C3 | 180.0 | 180.0 | 180.0 | — | | Br11–C1–C2–Br11 | 0.0 | 0.0 | 0.0 | — | | C2–C1–C6–C5 | 0.0 | 0.0 | 0.0 | — | | C2–C1–C6–H10 | 180.0 | 180.0 | 180.0 | — | | Br11–C1–C6–C5 | 180.0 | 180.0 | 180.0 | — | | Br11–C1–C6–H10 | 0.0 | 0.0 | 0.0 | — | | C1–C2–C3–C4 | 0.0 | 0.0 | 0.0 | — | | C1–C2–C3–H7 | 180.0 | 180.0 | 180.0 | — | | Cl12–C2–C3–C4 | 180.0 | 180.0 | 180.0 | — | | Cl12–C2–C3–H7 | 0.0 | 0.0 | 0.0 | — | | C2–C3–C4–C5 | 0.0 | 0.0 | 0.0 | — | | C2–C3–C4–H8 | 180.0 | 180.0 | 180.0 | — | | H7–C3–C4–C5 | 180.0 | 180.0 | 180.0 | — | | H7–C3–C4–H8 | 0.0 | 0.0 | 0.0 | — | | C3–C4–C5–C6 | 0.0 | 0.0 | 0.0 | — | | C3–C4–C5–H9 | 180.0 | 180.0 | 180.0 | — | | H8–C4–C5–C6 | 180.0 | 180.0 | 180.0 | — | | H8–C4–C5–H9 | 0.0 | 0.0 | 0.0 | — | | C4–C5–C6–C1 | 0.0 | 0.0 | 0.0 | — | | C4–C5–C6–H10 | 180.0 | 180.0 | 180.0 | — | | H9–C5–C6– C1 | 180.0 | 180.0 | 180.0 | — | | H9–C5–C6– H10 | 0.0 | 0.0 | 0.0 | — |
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