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been used to derive the R-dependent ionization rate of D + 2 in most previous studies [20–22]. In this figure, we also show the internuclear populations for the different time intervals shown in Fig. 3. This figure shows explic- itly that the high-energy band of the KER spectrum in Fig. 3, that is constructed between ∼ 4 . 8 − 8 cycles, has a strong ionization rate about ∼ 4 − 5 internuclear dis- tances and the low-energy band of the KER spectrum 

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(Fig. 3), that is constructed between ∼ 8 . 1 − 12 . 5 cycles, has a relatively strong ionization rate about ∼ 6 − 7 inter- nuclear distances. After 12.5 cycles, the intensity of the laser field becomes considerably low (Fig. 1) and a signif- icant population of D + 2 was becomes ionized as shown in Fig. 5. Therefore it is impossible to appear an enhanced ionization signal for larger internuclear distances. 

In Coulomb explosion imaging [23], we want to re- 

