. 2018 Oct 31;474(2218):20180075. doi: 10.1098/rspa.2018.0075

Table 2.

Estimated values of derivatives required to evaluate the anharmonic functions.

differential	value	reference
$\frac{\partial C_{33}}{\partial e_{z z}}$	−6 × 10¹¹ N m⁻²	[7]
	−5.5 × 10¹¹ N m⁻²	[55]
$\frac{\partial C_{44}}{\partial e_{z z}}$	−3.55 × 10¹⁰ N m⁻²	[9]
	−10 × 10¹⁰ N m⁻²	[9]
	−8.1 × 10¹⁰ N m⁻²	[8]
	−4.05 × 10¹⁰ N m⁻²	[7]
	−2.4 × 10¹⁰ N m⁻²	[55]
$\frac{\partial δ}{\partial e_{z z}}$	−1.4 × 10⁻⁷ m² s⁻¹	[9,56]
$\frac{1}{C_{11}} \frac{\partial C_{11}}{\partial e_{x x}}$	−8.2	[6]
$\frac{1}{(C_{11} - C_{12})} \frac{\partial (C_{11} - C_{12})}{\partial e_{x x}}$	−8.2	[6]
$\frac{1}{δ} \frac{\partial δ}{\partial e_{x x}}$	8.2	[6]