Syntax

Data is input in a `keyword <value>' fashion, and input is independent of the ordering of the input file. The value may be preceded by `=', `:' or a blank space or tab.

The keywords are case insensitive (e.g. unitCell is equivalent to UnItceLL) and punctuation insensitive (unit.cell is equivalent to unit_cell is equivalent to unitcell). Punctuation characters are `.' and `_'.

Physical quantities may be followed by a unit. The quantity will be automatically converted to atomic units, as used internally, when the file is read. The units which are recognised by the code for each physical dimension are listed in Tables 3.1 and 3.2. If no units are provided in the input, the assumed units will be those shown in these tables.

The following are equivalent ways of defining a physical quantity:

AgeOfUniverse = 24.d0 s
Age_Of_Universe : 24.d0 S
AgeOfUniverse 24.d3 ms

The input file can contain comments. These are defined as anything to the right of, and including, `#', `;', or `!'. Blank lines are ignored.

Block data is preceded by `%block <keyword>' followed by a series of lines, terminated by `%endblock <keyword>'.

Table 3.1: The units of length, mass, time, charge energy and force in which physical data may be input and output. The dimensions for which unit conversion is provided are as follows: L = length, M = mass, T = time, C = charge, E = energy, F = force, V = velocity, P = pressure, 1/L = reciprocal length, F/L = Force constant and Vol = Volume. The default for each dimension is indicated by a *. The relative values are given in terms of SI fundamental constants.

Unit	Abbreviation	Dimension	Identifier	Value
				(atomic units)
Bohr	Bohr	L	bohr,a0	1
Metre	m	L	m	$\frac{m_ec\alpha}{\hbar}$
Centimetre	cm	L	cm	$\frac{m_ec\alpha}{\hbar}\times 10^{-2}$
Nanometre	nm	L	nm	$\frac{m_ec\alpha}{\hbar}\times 10^{-9}$
Ångstrom*	A	L	ang	$\frac{m_ec\alpha}{\hbar}\times 10^{-10}$
Electron Mass	m_e	M	me	1
Unified Atomic Mass Unit*	amu	M	amu	$\frac{1}{N_Am_e} \times 10^{-3}$
Kilogram	kg	M	kg	$\frac{1}{m_e}$
Gram	g	M	g	$\frac{1}{m_e} \times 10^{-3}$
Atomic Unit of Time	aut	T	aut	1
Second	s	T	s	$\frac{c^2\alpha^2m_e}{\hbar}$
Millisecond	ms	T	ms	$\frac{c^2\alpha^2m_e}{\hbar} \times 10^{-3}$
Microsecond	mus	T	mus	$\frac{c^2\alpha^2m_e}{\hbar} \times 10^{-6}$
Nanosecond	ns	T	ns	$\frac{c^2\alpha^2m_e}{\hbar} \times 10^{-9}$
Picosecond*	ps	T	ps	$\frac{c^2\alpha^2m_e}{\hbar} \times 10^{-12}$
Femtosecond	fs	T	fs	$\frac{c^2\alpha^2m_e}{\hbar} \times 10^{-15}$
Elementary Charge*	e	C	e	1
Coulomb	Coulomb	C	c	$\frac{1}{e}$
Hartree	Ha	E	hartree,ha	1
Millihartree	mHa	E	mhartree	$10^{-3}$
Electron Volt*	eV	E	ev	$\frac{e}{\alpha^2m_ec^2}$
Milli-Electron Volt	meV	E	mev	$\frac{e}{\alpha^2m_ec^2} \times 10^{-3}$
Rydberg	Ry	E	ry	$\frac{1}{2}$
Millirydberg	mRy	E	mry	$5 \times 10^{-4}$
kJ/mol	kJ/mol	E	kj/mol	$\frac{1\times 10^3}{\alpha^2m_ec^2N_A}$
kcal/mol	kcal/mol	E	kcal/mol	$\frac{4.184\times 10^3}{\alpha^2m_ec^2N_A}$
Joule	J	E	j	$\frac{1}{\alpha^2m_ec^2}$
Erg	erg	E	erg	$\frac{1 \times 10^{-7}}{\alpha^2m_ec^2}$
Hertz	Hz	E	hz	$\frac{h}{\alpha^2m_ec^2}$
Megahertz	MHz	E	mhz	$\frac{h}{\alpha^2m_ec^2} \times 10^6$
Gigahertz	GHz	E	ghz	$\frac{h}{\alpha^2m_ec^2} \times 10^9$
Terahertz	THz	E	thz	$\frac{h}{\alpha^2m_ec^2} \times 10^{12}$
Wavenumber	cm-1	E	cm-1	$\frac{hc}{\alpha^2m_ec^2} \times 10^2$
Kelvin	K	E	k	$\frac{k}{\alpha^2m_ec^2}$
Hartree/Bohr	Ha/Bohr	F	hartree/bohr	1
eV/	eV/A	F	ev/ang	$\frac{e\hbar}{\alpha^3m_e^2c^3} \times 10^{10}$
Newton	N	F	n	$\frac{\hbar}{\alpha^3m_e^2c^3}$
dyne	dyne	F	dyne	$\frac{\hbar}{\alpha^3m_e^2c^3} \times 10^{-5}$

Table 3.2: The units of velocity, pressure, reciprocal length, force constant and volume in which physical data may be input and output. The dimensions for which unit conversion is provided are as follows: L = length, M = mass, T = time, C = charge, E = energy, F = force, V = velocity, P = pressure, 1/L = reciprocal length, F/L = Force constant and Vol = Volume. The default for each dimension is indicated by a *. The relative values are given in terms of SI fundamental constants.

Unit	Abbreviation	Dimension	Identifier	Value
				(atomic units)
Atomic Unit of Velocity	auv	V	auv	1
Ångstom/ps*	A/ps	V	ang/ps	$\frac{1}{c\alpha}\times 10^2$
Ångstom/fs	A/fs	V	ang/fs	$\frac{1}{c\alpha}\times 10^5$
Bohr/ps	Bohr/ps	V	bohr/ps	$\frac{\hbar}{c^2\alpha^2m_e} \time 10^{12}$
Bohr/fs	Borh/fs	V	bohr/fs	$\frac{\hbar}{c^2\alpha^2m_e} \time 10^{15}$
Metre/Second	m/s	V	m/s	$\frac{1}{c\alpha}$
Hartree/Bohr$^3$	Ha/Bohr**3	P	hartree/bohr**3	1
eV/Ångstrom$^3$	eV/A**3	P	ev/ang**3	$\frac{e\hbar^3}{\alpha^5c^5m_e^4} \times 10^{30}$
Pascal	Pa	P	pa	$\frac{\hbar^3}{\alpha^5m_e^4c^5}$
Megapascal	MPa	P	mpa	$\frac{\hbar^3}{\alpha^5m_e^4c^5} \times 10^6$
Gigapascal*	GPa	P	gpa	$\frac{\hbar^3}{\alpha^5m_e^4c^5} \times 10^9$
Atmosphere	Atm	P	atm	$\frac{101325.027 \hbar^3}{\alpha^5m_e^4c^5} \times 10^6$
bar	bar	P	bar	$\frac{\hbar^3}{\alpha^5m_e^4c^5} \times 10^5$
Megabar	Mbar	P	mbar	$\frac{\hbar^3}{\alpha^5m_e^4c^5} \times 10^{11}$
Bohr$^-1$	1/Bohr	1/L	1/bohr	1
Metre$^-1$	1/m	1/L	1/m	$\frac{\hbar}{m_ec\alpha}$
Nanometre$^-1$	1/nm	1/L	1/nm	$\frac{\hbar}{m_ec\alpha}\times 10^{9}$
Ångstrom$^-1$*	1/A	1/L	1/ang	$\frac{\hbar}{m_ec\alpha}\times 10^{10}$
Hartree/Bohr$^2$	Ha/Bohr**2	F/L	ha/bohr**2	1
ev/Ångstrom$^2$*	ev/A**2	F/L	ev/ang**2	$\frac{e\hbar}{\alpha^3m_e^2c^3} \times 10^{10}$
Newton/metre	N/m	F/L	n/m	$\frac{\hbar^2}{\alpha^4m_e^3c^3}$
dyne/centimetre	dyne/cm	F/L	dyne/cm	$\frac{\hbar^2}{\alpha^4m_e^3c^3} \times 10^{-3}$
Bohr$^3$	Bohr**3	Vol	bohr**3	1
Metre$^3$	m**3	Vol	m**3	$\left( \frac{m_ec\alpha}{\hbar} \right)^3$
Centimetre$^3$	cm**3	Vol	cm**3	$\left( \frac{m_ec\alpha}{\hbar} \right)^3 \times 10^{-6}$
Nanometre$^3$	nm**3	Vol	nm**3	$\left( \frac{m_ec\alpha}{\hbar} \right)^3 \times 10^{-27}$
Angstrom$^3$	A**3	Vol	ang**3	$\left( \frac{m_ec\alpha}{\hbar} \right)^3 \times 10^{-30}$