Highly efficient passively Q-switched Tm: YAP laser using a Cr: ZnS saturable absorber

To evaluate the stability,heat-resistance ability and thermal safety of mnpp(1h,4h-3-methyl-6-nitro-pyrazolo[4,3-c]pyrazole),cnpp (1h,4h-3-carboxy-6 -nitro-pyrazolo[4,3-c]pyrazole),dnpp (1h,4h-3,6-dinitro-pyrazolo [4,3-c] pyrazole),the theoretical investigation on mnpp,cnpp and dnpp was performed by the dft-b3lyp/6-31g level using gaussian 09w program. the theoretical density (ρ) of the compounds was obtained by quantum chemical method. the kamlet-jacobs formulas were employed to calculate the detonation properties including the detonation velocity (d) and pressure (p). their thermal behaviors were investigated by differential scanning calorimetry (dsc),thermogravimetry-derivative thermogravimetry (tg-dtg) and in-situ cell thermolysis/rapid-scan fourier transform infrared spectroscopy (rsft-ir). results show that (1) using critical temperature of thermal explosion,free energy of activation of decomposition reaction and self-accelerating decomposition temperature as criterions,the thermal stability,heat resistance ability and thermal safety of the three compounds decrease in the order of dnpp > mnpp >cnpp,but using energy gap and total energy as criterions,the thermal stability decreases in the order of dnpp > cnpp > mnpp,therefore,dnpp is the most stable compound among the three compounds; (2) among of the three compounds,dnpp possesses the maximum theoretical density (1.80 g•cm-3),the fastest detonation velocity (8.49 km•s-1) and the highest detonation pressure (31.96 gpa),suggesting that dnpp has good detonation properties and potential use in energetic material.