Research Article

Combination of a Green and a Traditional Method for Estimating Relative and Absolute Ink Age: A Case Study of Ballpoint Pen Ink Dating in Vietnam

Table 3

Peak wavelength number (cm−1) and reference data for reference dyes and samples M1, A3.2, and A3.1.

M1 (50 months)A3.2 (39 months)A3.1 (date)Reference data [6]Type of vibrations

525525525524 (CV)δ (CNC)
+++558 (CV)γ (CCC)/δ (CNC)/δ (CC center C)
726724726724 (CV)ν (CN)
912916912915 (CV)ν (CC) ring
997993997995 (MY)
1137114111411147 (MY)
1184118011801178 (CV)νs (CC center C)/δ (CCC) breathing /δr (CH 3 )
1188118811881188 (MY)
1300129513061300 (CV)νas (CC center C)/δ (CCC) ring /δ (CH)
1361136513651369 (CV)ν (CC center C)
1430143614281447 (CV)δas (CH 3 )
1539154015341536 (CV)ν (C ring N)/δs (CH 3 )
1586158215861591 (CV)ν (C-C) ring
+162216221622 (CV)ν (C-C) ring

, stretching vibrations; δ, planar deformation vibrations; s, symmetric; “+,” small peak observed; as, asymmetric. Values in bold indicate the matching peaks of crystal violet (CV). Values in italics indicate the matching peaks of metanil yellow (MY).