N–H collision integrals with study of repulsive interactions

Abstract

Abstract Collision integrals are calculated and analyzed for the ground state nitrogen N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi mathvariant="normal">S</mml:mi> </mml:mrow> <mml:none/> <mml:none/> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> and hydrogen H <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi mathvariant="normal">S</mml:mi> </mml:mrow> <mml:none/> <mml:none/> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> atoms involving the 3 Σ and 5 Σ electronic states in the temperature range of 1000–30 000 K. Influence of the quality of different known potential energy functions on the collision integrals was also studied and compared with the available data. Based on our analysis, the repulsive potential and its description beyond simple exponential also at small interatomic distances is necessary to obtain reliable collision integrals. Besides the ground state atoms, for the first time the collision integrals for excited nitrogen atoms (N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi mathvariant="normal">D</mml:mi> </mml:mrow> <mml:none/> <mml:none/> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> and N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi mathvariant="normal">P</mml:mi> </mml:mrow> <mml:none/> <mml:none/> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> ) with ground state hydrogen H <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi mathvariant="normal">S</mml:mi> </mml:mrow> <mml:none/> <mml:none/> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> were also calculated. The corresponding potential energy curves are also computed by using multireference configuration interaction (MRCI) method of electronic structure theory with aug-cc-pV6Z basis set. The resulting collision integrals were fitted to simple functional forms.

Topics & Concepts